Methods and devices for intracorporeal bonding of implants with thermal energy

ABSTRACT

The present invention provides a method for stabilizing a fractured bone. The method includes positioning an elongate rod in the medullary canal of the fractured bone and forming a passageway through the cortex of the bone. The passageway extends from the exterior surface of the bone to the medullary canal of the bone. The method also includes creating a bonding region on the elongate rod. The bonding region is generally aligned with the passageway of the cortex. Furthermore, the method includes positioning a fastener in the passageway of the cortex and on the bonding region of the elongate rod and thermally bonding the fastener to the bonding region of the elongate rod while the fastener is positioned in the passageway of the cortex.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 11/671,556, filed Feb. 6, 2007. The '556Application claimed the benefit of the following U.S. ProvisionalApplications: 60/765,857 filed February 2006; 60/784,186 filed Mar. 21,2006; and 60/810,080 filed Jun. 1, 2006. This application is also acontinuation-in-part of U.S. patent application Ser. No. 11/416,618filed May 3, 2006. The entirety of these related applications areincorporated by reference.

FIELD OF THE INVENTION

The invention relates to fixation of tissues and implants within thebody, such as the fixation of two different tissue types, the fixationof an implant to tissue, or the fixation of an implant to anotherimplant. This may involve using an energy source to weld biocompatiblematerials intracorporeally to stabilize tissue within a patient's body,such as a fractured bone.

BACKGROUND OF THE INVENTION

Body tissue often requires repair and stabilization following traumasuch as a fractured bone, torn ligament or tendon, ripped muscle, or theseparation of soft tissue from bone. For example, trauma to the rotatorcuff usually results in a portion, if not all, of the ligament beingtorn away from bone. To repair such an injury, the rotator cuff must berepositioned to its anatomically correct location and secured to thebone.

One method of repairing a damaged rotator cuff is through the use of abone anchor and a suture. A hole is drilled in the bone near where therotator cuff will be reattached to the bone. Then, an instrument is usedto place a mattress stitch with a suture in the detached portion of therotator cuff. The suture is slideably positioned through the anchor, andthe anchor is placed in the bone hole using an insertion instrument.This instrument includes an anvil and mandrel placed in contact with theanchor so that when the anvil and mandrel are moved in oppositedirections relative to each other, the anchor is deformed. Thedeformation locks the anchor within the bone. Thereafter, the suture istensioned drawing the rotator cuff toward the anchor. A suture lock isthen activated by the insertion instrument to thereby pinch the suturebetween the anchor and suture lock.

In another example, fractured bones are a common injury seen in traumacenters. Sports activities, vehicle accidents, industrial-typeincidents, and slip and fall cases are just a few examples of how bonesmay become fractured. Surgeons in trauma centers frequently encountermany different types of fractures with a variety of different bones.Each bone and each fracture type may require unique procedures anddevices for repairing the bone. Currently, a one-solution-fixes-alldevice is not available to repair fractured bones. Instead, surgeons mayuse a combination of bone screws, bone plates, and intramedullary rods.

Bone plates may be positioned internal to the skin, i.e. positionedagainst the fractured bone, or may be positioned external to the skinwith rods connecting the bone and plate. Conventional bone plates areparticularly well suited to promote healing of the fracture bycompressing the fracture ends together and drawing the bone into closeapposition with other fragments and the bone plate. However, onedrawback with plates and screws is that with the dynamic loading placedon the plate, loosening of the screws and loss of stored compression canresult.

To reduce the potential of loosening, locking screws and a locking boneplate may be used. U.S. Pat. No. 5,085,660 to Lin discloses a lockingplate system. The system has multiple locking pins, each with one endformed as a screw to lock in the pending fixation bones or vertebraltubercles, with another end defining rectangular or similarly shapedlocking post having a threaded locking end. Near the locking post end,there is formed a stopping protrusion. A plate defines multiple lockingbores disposed at one side to be placed over the locking post end untilthe plate reaches the stopping protrusion on the locking pin. The platedefines multiple threaded screwing bores near the other side to receivelocking pin screw. Multiple locking devices fix the side of the platehaving locking bores to the locking post end of its locking pins.Multiple screwing pins each have one end formed as a pin to be used forpenetrating the threaded screwing bore to lock into the bone or thevertebral tubercle. Another end which forms a head is for holdingagainst the threaded screwing bore of the plate. Threads are providednear the head for the screwing pins to be screwed within the threadedscrewing bore of the plate.

An example of an external bone plate system is disclosed in U.S. Pat.No. 6,171,307 to Orlich. Orlich teaches an apparatus and procedure forthe external unilateral fracture fixation, fracture compression orenlargement of osseous tissue with a metal or equivalent materialslotted forked stick to hold and position the threaded pins in itslength, inserted in the bone with multiple fastening slidable screws andtheir bolts to attach the pins to the slotted forked stick, a solidslidable cube to hold and position the slotted forked stick, asupporting axial bar, and an axial threaded bar. A preferred embodimentincludes at least three slotted forked sticks that hold and fix, withthe use of compression screws and their bolts, threaded pins thatpenetrate the proximal and distal fragments of the bone through bothcorticals. Another preferred embodiment includes slotted forked sticksthat adapt to the threaded pins, introduced in the bone, at any degreeof inclination or orientation that these pins might have with respect tothe bone.

In addition to internal or external bone plates, surgeons sometimes useintramedullary rods to repair long bone fractures, such as fractures ofthe femur, radius, ulna, humerus, fibula, and tibia. The rod or nail isinserted into the medullary canal of the bone and affixed therein byscrews or bolts. After complete healing of the bone at the fracturesite, the rod may be removed through a hole drilled in the end of thebone. One problem associated with the use of today's intramedullary rodsis that it is often difficult to treat fractures at the end of the longbone. Fastener members, such as bolts, are positioned through thecortical bone and into threaded openings in the rod. However, the numberand positioning of the bolt/screw openings are limited at the tip of therod. Therefore, fractured bone sections at the distal end of a femur,for example, may not be properly fastened to the intramedullary rod.

Various inventions have been disclosed to repair tissue and fastenimplants to tissue. U.S. Pat. No. 5,120,175 to Arbegast et al. disclosesa fastener having an elongated shank formed of a shape memory alloy, ahead at the upper end of the shank, and an annular segment at the lowerend of said shank having a deformed cross-sectional shape suitable forinsertion into an opening extending through adjacent workpieces. Theannular segment has a frusto-conical trained shape that is larger thanthis opening. The annular segment radially flares from the deformedshape to an approximation of the trained shape when heated above acritical transformation temperature, thereby securing the fastener inplace with respect to the workpieces. Alternatively, a sleeve made of adifferent material (e.g. aluminum) extending over a portion or theentire length of the fastener can be added for improved deformationalcharacteristics, by providing the same frusto-conical shape throughaxial contraction of the shank.

U.S. Pat. No. 5,290,281 to Tschakaloff teaches a surgical systemincluding a thermoplastic, body absorbable, bodily tissue fixation platehaving a plurality of formations and a plurality of through-boresarranged in alternating relation along with plate. The body absorbablefasteners are adapted for insertion into the through-bores to secure theplate to underlying bodily tissue. The heating apparatus includes a wandhaving a heating tip of a configuration adapted to substantiallymatingly cooperate with the formations to facilitate heating and bendingof the plate into conformance with the underlying bodily tissue.

U.S. Pat. No. 5,941,901 to Egan discloses an expandable soft tissuefixation assembly for use in anchoring soft tissue to bone. The assemblyincludes a tab connected to an anchor, a sleeve adapted to surround theanchor, and a flange adapted to hold a soft tissue segment next to abone. The sleeve is inselied into a blind hole in a bone, and a sectionof soft tissue is placed over the hole next to the bone. Energy isapplied to the flange while a predetermined axial tension is applied tothe tab to compress a flared portion of the anchor against the sleeve.An upper tube portion of the anchor and the flange are bonded together,and the applied axial force on the tab separates it from the anchor,leaving the assembly anchored in the bone and the soft tissue sectionanchored in place between the flange and the bone.

U.S. Pat. No. 7,018,380 to Cole discloses a femoral intramedullary rodsystem. The rod system is capable of treating a variety of femoral bonefractures using a uniform intramedullary rod design. The systemgenerally comprises an intramedullary rod defining an opening having anupper surface and a transverse member including a bone engaging portionand a connection portion defining a thru-hole with the nail sized topass therethrough. A pin is selectively coupled to the transverse memberto rigidly assemble the transverse member to the nail when the nail ispassed through the thru hole and the pin is received within the opening.In an alternative design, an epiphyseal stabilizer is joined to the nailby a locking member.

Also, U.S. Pat. No. 6,228,086 to Wahl et al. discloses a modularintramedullary nail. The intramedullary nail apparatus comprises a nailhaving a proximal portion, a middle portion and a distal portion. Theproximal portion has a longitudinal slot adapted to receive at least onefixing element and the distal portion has at least one transverse bore.The proximal portion has a longitudinal axial bore. The apparatusfurther includes a set of inserts, each of which is adapted to beinserted in the longitudinal bore. Each insert has at least one guidingbore, the orientation and position of which is different for each of theinserts.

Another assembly and method to fasten tissue is disclosed in U.S. Pat.No. 6,056,751 to Fenton et al. Fenton teaches a soft tissue fixationassembly comprising an anchor element which is installed in a bone orother tissue, and a joiner element which mates with the anchor elementto define a tissue capture region between them. A section of soil tissueis held within the tissue capture region, and energy is transmitted intothe joiner element to cause relative vibratory motion between therespective components and localized melting of the contacting portionsof the respective components to establish a welded joint. The softtissue segment is thus fixed to the bone without sutures or otherfasteners.

U.S. Pat. No. 6,080,161 to Eaves, III et al. teaches a fastener forsecuring an osteosynthesis plate to a plurality of bone segments isprovided. The fastener in the form of a fastener blank includes anelongated shank adapted for insertion through an opening in the plateand into a hole formed in the bone. The upper end of the shank forms ahead that serves to secure the plate to the bone. The elongated shank isconstructed of a material which when heated will deform to form a tightfit within the hole drilled in the bone. The fastener is preferably madeof a resorbable material. The invention also provides a method forsecuring a plate to a bone using the fasteners of the invention. Afastener blank is positioned into the hole so that a portion of theblank extends into the hole provided in the bone and another portionoverlies the plate. The blank is heated to raise the temperature of theblank above the transition temperature of the material from which it ismade and deform the blank into a tight fit within the hole.

U.S. Pat. No. 6,605,090 to Trieu et al. discloses orthopedic implantsand methods of treating bone defects. More specifically, but notexclusively, the present invention is directed to non-metallic implantsand to methods for intra-operative assembly and fixation of orthopedicimplants to facilitate medical treatment. The non-metallic implantassembly can be secured to underlying tissue by a fastener, such as abone screw, that is capable of swelling on contact with fluid in theunderlying tissue. Alternatively, the non-metallic implant assembly canbe assembled intra-operatively using a fastener that is adhesivelybonded to a bone plate or the bone plate can be deformed using heat,force or solvents to inhibit withdrawal of the fastener. In preferredembodiments, both the fastener and the bone plate are formed ofbiodegradable material.

Also, U.S. Patent Publication No. 2004/0030341 to Aeschlimann et al.teaches implants at least partially consist of a material that can beliquefied by means of mechanical energy. Particularly suitable materialsof this type are thermoplastics (e.g. resorbable thermoplastics) orthixotropic materials. The implants are brought into contact with thetissue part, are subjected to the action of ultrasonic energy and aresimultaneously pressed against the tissue part. The liquefiable materialthen liquefies and is pressed into openings or surface asperities of thetissue part so that, once solidified, it is positively joined thereto.The implantation involves the use of an implantation device comprising agenerator, an oscillating clement and a resonator, whereby the generatorcauses the oscillating element to mechanically oscillate, and theelement transmits the oscillations to the resonator. The resonator isused to press the implant against the tissue part whereby causingoscillations to be trmlsmitted to the implant. The implants are, forexample, pin-shaped or dowel-shaped and are used in lieu of screws forforming connections with bone tissue, whereby the bone tissue isoptionally pre-bored for positioning the implant. By viliue of the factthat it is unnecessary to transmit any torsional forces to the implants,these implants can be provided with a design that is weaker, i.e.slimmer than that of known screws made of the same material, and theycan be implanted more quickly.

Existing systems and techniques for repairing tissue, like the onespreviously described, can be complex, time consuming, lack thecharacteristic of being employed with precision, be damaging to tissue,and/or fail to provide a robust fixation of tissue. Therefore, there isa need for an apparatus and method for the fixation of tissue thatinvolves reduced technical ability, fewer medical instruments, less timeto complete, greater strength and precision, and preservation of livingtissue. There is a need for a system that involves the preciseapplication of energy to thermoplastic material to affix tissue andimplants within the body.

SUMMARY OF THE INVENTION

The present invention provides devices and methods for the fixation oftissue or implants during a surgical procedure. The system includesdevices and methods for intracorporeal bonding of thermoplasticmaterial. An energy source welds the thermoplastics to polymers, metals,ceramics, composites, and tissue. The energy source may be resistiveheating, radiofrequency, ultrasound (vibratory), microwave, laser,electromagnetic, electro shockwave therapy, plasma energy (hot or cold),and other suitable sources.

In one embodiment of the invention, a fixation device includes atissue-piercing cap positionable in the anchor. Hard and soil tissue maybe fastened so that tissue-function may be at least partially restoredand the operation region may be stabilized for enhanced healing. Thiscould be ligament repair, tendon repair, muscle repair, bone repair,cartilage repair, and repair of any other tissue type. Ligaments may befastened to ligaments; ligaments to bones; bones to bones; ligaments tomuscles; muscles to muscles; tissue grafts to bone; tissue grafts toligaments; grafts to grafts; and any other combination of tissue andimplants.

Another embodiment of the invention is directed to a trauma weldingsystem that helps stabilize tissue or implants. In some embodiments, thesystem may include devices and methods for intracorporeal bonding ofthermoplastic material. An energy source welds the thermoplastics topolymers, metals, ceramics, composites, and tissue. The energy sourcemay be resistive heating, radiofrequency, ultrasound (vibratory),microwave, laser, electromagnetic, electro shockwave therapy, plasmaenergy (hot or cold), and other suitable sources. The energy source alsomay enable at least part of the implanted material to be foamed.

Several embodiments of the invention involve a trauma welding systemthat utilizes material that can be welded within the human body. Thismaterial has requires the characteristic of becoming soft and tacky withthe application of energy. The energy and techniques used to weld thematerial within the body are preferably selected to avoid or minimizethe likelihood of tissue necrosis. Such material may include polymersand some ceramics, composites, and metals. The present inventioncontemplates the use of any of these materials; however, based ontesting, it is believed that polymeric material, such as PEEK and PLLA,are preferred weldable materials. PEEK and PLLA are advantageous becauseof their desirable characteristics of being softened, reheated, moldedand remolded. These characteristics are believed to exist even with theuse of ultrasonic energy as the energy source to weld the material. Theuse of solder and ultrasonic energy are preferred when weldingelectrical or electronic wires and components intracorporeally.

In accordance with one aspect of the present invention, there isprovided a method for stabilizing a fractured bone. The method includesthe steps of positioning an elongate rod in the medullary canal of thefractured bone and forming a passageway through the cortex of the bone.The passageway extends from the exterior surface of the bone to themedullary canal of the bone. The method also includes creating a bondingregion on the elongate rod where the bonding region is generally alignedwith the passageway of the cortex, positioning a fastener in thepassageway of the cortex and on the bonding region of the elongate rod,and thermally bonding the fastener to the bonding region of the elongaterod while the fastener is positioned in the passageway of the cortex.

In accordance with another aspect of the present invention, anothermethod for stabilizing a fractured bone includes positioning an elongateplate on the exterior surface of a fractured bone, forming a passagewayextending through the elongate plate and into the bone, positioning afastener in the passageway, and thermally bonding the fastener to thebone while the fastener is positioned in the passageway.

Yet another embodiment of the invention involves stabilizing a fracturedbone by positioning an elongate rod in the medullary canal of thefractured bone and positioning an elongate plate on the exterior surfaceof the bone such that the cortex of the bone is positioned between theelongate rod and plate. This method may also include forming apassageway through the elongate plate and the cortex of the bone. Thepassageway extends from the exterior surface of the elongate plate tothe medullary canal of the bone. The method may further include creatinga bonding region on the elongate rod where the bonding region isgenerally aligned with the passageway, positioning a fastener in thepassageway and on the bonding region of the elongate rod, and thermallybonding the fastener to the bonding region of the elongate rod while thefastener is positioned in the passageway.

The elongate rod, elongate plate, and fastener may include thermoplasticmaterial such as PEEK. Ultrasonic energy may be used to thermally bondfasteners to the bonding region of the elongate rod and/or elongateplate. The bonding region may be a roughened surface, an indentation, achannel (blind hole), or a thru-hole in the plate/rod.

When bonding the fastener to the plate/rod, the fastener may also bethermally welded to one or more cortex areas (cortical bone portions) ofthe bone whereby the fastener resists movement between the bone andplate/rod. Also, the fastener and implants such as bone plates and IMrods may be thermally contoured to conform to an adjacent surface orconfiguration.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view of an exemplary ultrasound welding device;

FIGS. 2A and 2B illustrate exemplary cartridge heaters of the presentinvention;

FIGS. 3A-3K show exemplary embodiments of a welding horn;

FIGS. 4A-4C illustrate a three-function welding horn;

FIG. 5 shows the input parameters of a welding control unit;

FIG. 6 illustrates a manual welding control box;

FIG. 7 shows a control box having pre-set welding parameters;

FIG. 8A illustrates an automatic welding control unit;

FIG. 8B is a photograph of an ultrasonic welding control unit;

FIG. 8C is a graph showing a welding profile having varying wattage;

FIG. 9 is a flowchart showing the steps for adjusting the weldingdevice;

FIG. 10 is a diagram showing an electrical circuit for checking thewelding device;

FIGS. 11A and 11B illustrate a physical positive feedback device;

FIGS. 12A-12F show various embodiments of thermoplastic fasteners;

FIGS. 13A and 13B illustrate bonding regions of implants;

FIGS. 14A-14D show more embodiments of thermoplastic fasteners;

FIGS. 15A and 15B illustrate notched plates and rods for stabilizingbones;

FIGS. 16A and 16B show a wedge-shaped expandable thermoplastic fastener;

FIGS. 17A and 17B illustrate a bulge-shaped expandable fastener;

FIGS. 18A and 18B show a mesh expandable fastener;

FIGS. 19A and 19B illustrate a tube-shaped expandable fastener;

FIGS. 20A-20E show triangulation fasteners;

FIG. 21 is a welding horn for a triangulation fastener;

FIGS. 22A and 22B illustrate a thermoplastic implant removal device;

FIGS. 23A-23D show the repair of a fractured bone with a thermoplasticrod;

FIGS. 24A and 24B illustrate the repair of a fractured head of a bone;

FIGS. 25A and 25B show the repair of a fractured bone with athermoplastic plate;

FIGS. 26A and 26B illustrate the repair of a fractured bone with acombination of a thermoplastic rod and plate;

FIGS. 27A-27C show a bone plate of the present invention;

FIGS. 28A-28D illustrate exemplary fasteners for use with a bone plateor other implant;

FIG. 29 shows modular assembly of a spinal implant;

FIG. 30 illustrates sequential welding of an intramedullary rod;

FIGS. 31A and 31B show the stabilization of the spine usingthermoplastic implants;

FIG. 32 illustrates an exemplary embodiment of a pedicle implant;

FIG. 33 shows stabilization of the spinal column with thermoplasticimplants;

FIGS. 34A and 34B illustrate a pedicle fastener apparatus;

FIGS. 35A and 35B show a thermoplastic bone fixation assembly;

FIGS. 36A and 36B illustrate a thermoplastic suture tensioning device;

FIG. 37 shows the tensioning device of FIGS. 36A and 36B in use tostabilize the spine;

FIGS. 38A-38C illustrate a thermoplastic glenoid repair component;

FIG. 39 shows a thermoplastic cross pin;

FIG. 40 illustrates a jig device for use with the cross pin of FIG. 39;

FIG. 41 shows cauterization of tissue using ultrasonic energy;

FIG. 42 illustrates cauterization of tissue using energy and gelatin;

FIG. 43 shows the repair of tissue with a periosteal flap;

FIGS. 44A and 44B illustrate a method of bonding a thermoplasticfastener in bone.

FIG. 45 illustrates a perspective view of one embodiment of a fixationdevice of the present invention;

FIG. 46 illustrates an exemplary process for ultrasonic welding;

FIG. 47A shows a side view of the fixation device of FIG. 45 with a cappositioned in the anchor and an energy source disposed within the capand anchor;

FIG. 47B is a cross sectional view of FIG. 47A;

FIG. 48 illustrates the fixation device of FIG. 45 with a pusher meanspositioned against the cap;

FIG. 49 shows the fixation device of FIG. 45 employed to fasten tissue;

FIG. 50 is a cross-sectional view of another embodiment of a fixationdevice being free of a mechanical locking means;

FIG. 51 shows yet another embodiment of a fixation device having athreaded cap;

FIG. 52 illustrates a further embodiment of a fixation device having aplurality of post ribs;

FIG. 53 is a cross-sectional view of another embodiment of a fixationdevice having an expandable anchor with radially extending projections;

FIG. 54 illustrates the fixation device of FIG. 53 in an expandedconfiguration;

FIG. 55 shows yet another embodiment of a fixation device having anexpandable anchor with a substantially smooth exterior,tissue-contacting surface;

FIG. 56 illustrates the fixation device of FIG. 55 in an expandedconfiguration;

FIG. 57A-D are perspective views illustrating the steps of deploying thefixation device of the present invention;

FIG. 58 illustrates a use of a fixation device to stabilize a fracturedbone;

FIG. 59 shows another embodiment of a fixation device having a suturepositioned therethrough;

FIG. 60 is a perspective view illustrating an embodiment of the fixationdevice having an integrated suture therein;

FIG. 61 shows yet another embodiment having a suture positioned in achannel and groove of the anchor;

FIG. 62 illustrates a different embodiment of the fixation device inwhich the anchor has a post and the cap has a post bore;

FIGS. 63A and 63B show a fixation device having a plurality of capsconnectable to a plurality of anchor posts;

FIGS. 64A and 64B illustrate an embodiment having an anchor with aplurality of bores in which a plurality of cap posts is positionable;

FIGS. 65A and 65B are perspective views of another embodiment of afixation device having an anchor with friction ribs and slots;

FIG. 66 shows a fixation device having an anchor with a substantiallysmooth outer surface and a plurality of slots disposed in the anchorwall;

FIG. 67 is a perspective view of a triangulation fixation device;

FIG. 68 is a side view of the triangulation device of FIG. 67;

FIG. 69 is a perspective view of another embodiment of a triangulationfixation device;

FIG. 70 is a side view of the triangulation device of FIG. 69;

FIG. 71 is another exemplary embodiment of a fixation device havinghelical threads and a retaining ring disposed on the cap post;

FIG. 72 is a perspective view of a further embodiment of a fixationdevice having an anchor post and a tissue-piercing pin;

FIG. 73 illustrates the device of FIG. 72 in use

FIGS. 74A and 74B show an exemplary fastener having four biasing prongs;

FIGS. 75A and 75B illustrate a fastener having lockable barbs;

FIGS. 76A and 76B show an exemplary fastener having two biasing prongs;

FIGS. 77A and 77B illustrate a fastener having slideable hooks;

FIGS. 78A and 78B show an exemplary fastener having folding arms;

FIGS. 79A and 79B illustrate a fastener having biasing prongs and atapered cap;

FIGS. 80A and 80B show an exemplary fastener having biasing prongs and amacrotexture welding region;

FIG. 81 is a cross sectional view of a fastener with a metallic core;

FIG. 82 is a cross sectional view of a fastener with a composite/polymercore;

FIGS. 83A and 83B show a balloon fastener of the present invention;

FIGS. 84A and 84B illustrate a living hinge fastener;

FIGS. 85A and 85B show a dual living hinge fastener;

FIGS. 86A and 86B illustrate a dual living hinge fastener with aretaining sheath;

FIG. 87 is photograph of a thermoplastic fastener positioned in bone;

FIG. 88 is a photograph of a biasing prong fastener disposed in bone;

FIG. 89 is a photograph showing thermoplastic fasteners welded intosimulated bone;

FIG. 90 is a photograph of metallic core fasteners disposed in athermoplastic rod;

FIG. 91 is an x-ray image of the fasteners and rods of FIG. 90;

FIGS. 92A and 92B are photographs of thermoplastic fasteners disposed inbone;

FIG. 93 shows a thermoplastic mesh sheet of the present invention;

FIG. 94 illustrates a helically wrapped mesh sheet;

FIG. 95 shows a thermoplastic mesh cylinder;

FIG. 96 illustrates a thermoplastic mesh cylinder thermally shaped intoa curved mesh tube;

FIG. 97 shows a mesh cylinder positioned about an aneurysm of a vessel;

FIG. 98 illustrates a mesh cylinder disposed around an anastomosissurgery area;

FIG. 99 shows an ultrasonic generator control unit and a handpiecepositioned adjacent tissue;

FIG. 100 illustrates modular implants for revision surgery;

FIG. 101A shows a thermally welded layered implant;

FIG. 101B illustrates a plyweld having metallic components weldedtogether with thermoplastics;

FIG. 101C shows a plyweld having polymeric components welded togetherwith thermoplastics;

FIG. 101D illustrates a plyweld having various components weldedtogether;

FIGS. 102A-102D illustrate various microtextures for use with welding;

FIGS. 103A-103F show various macrotextures for use during welding;

FIG. 104 illustrates a tibial tray component of the present invention;

FIG. 105 shows a tibia implant secured with thermoplastic fasteners;

FIG. 106 illustrates the repair of the proximal end of the tibia;

FIG. 107 shows bone filler components and a tibia implant secured tobone;

FIG. 108 illustrates a bone filler component and an acetabular implantfastened to bone;

FIGS. 109A and 109B show impact fracture repair using thermoplastic andmetallic components and ultrasonic energy;

FIGS. 110A and 110B illustrate an acetabular implant of the presentinvention;

FIGS. 111A and 111B show implantation and repair of electricalcomponents intracorporeally;

FIGS. 112A and 112B illustrate modular metallic stents;

FIGS. 113A and 113B show modular bifurcated metallic stents;

FIG. 114 illustrates welded bone filler and an implant;

FIGS. 115A and 115B show a thermally bonded suture knot;

FIG. 116 illustrates a shrinkable suture;

FIGS. 117A and 117B show thermally sealed implantable sacs;

FIGS. 118A and 118B illustrate tissue bonded with thermoplasticmaterial;

FIGS. 119A and 119B show a composite fastener of the present invention;

FIG. 120 illustrates an exemplary thermoplastic fastener used fortesting weld parameters;

FIG. 121 is a photograph showing the apparatus used for determining thefail strength of thermoplastics;

FIG. 122 is a photograph of thermoplastic fastener of the presentinvention;

FIG. 123 is a photograph of neoprene (used as a tissue model) held bythe fastener of FIG. 122;

FIG. 124 is a photograph of another fastener of the present invention;

FIG. 125 is a photograph of neoprene held by the fastener of FIG. 124;

FIG. 126 is a photograph of a test specimen with PEEK fasteners weldedtherein;

FIG. 127 is a photograph showing a PEEK fastener extending through atest specimen;

FIG. 128 is a photograph of a PEEK fastener welded into a blind hole;

FIG. 129 is a photograph showing a PEEK bone plate and PEEK fastenersused to repair a fractured bone test specimen;

FIG. 130 is a side view photograph of FIG. 129;

FIG. 131 is a photograph of a PEEK anchor which is mechanically lockedand thermally locked into a test specimen;

FIG. 132 is a photograph showing various PEEK fasteners andstabilization plates;

FIG. 133 is a photograph of a carbon reinforced PEEK specimen andfasteners;

FIG. 134 is a partial close-up photograph of FIG. 133;

FIG. 135 is a perspective view of an exemplary fastener and anchor;

FIG. 136 is a perspective view of an apparatus used during thermoplasticweld testing;

FIG. 137 is a table showing test results for PEEK ultrasonic weldsamples;

FIG. 138 is a table showing test results for Acrylic heat stake samples;

FIG. 139 is a perspective view of an exemplary ultrasound weldingdevice;

FIG. 140 is perspective view of a fastener and an end effector of thedevice of FIG. 139

FIG. 141 is a perspective view of the fastener disposed against the endeffector of FIG. 140;

FIG. 142 is a perspective view showing an energy source horn in contactwith a thermoplastic fastener which is disposed in a tissue anchor;

FIGS. 143A and 143B illustrate an exemplary cartridge heater of thepresent invention;

FIGS. 144A-144K show exemplary embodiments of a welding horn;

FIGS. 145A and 145B show a thermoplastic anchor welded in tissue;

FIG. 146 illustrates the repair of a fractured bone with thermoplasticsand energy;

FIG. 147 shows a thermoplastic fastener and anchor used to repair afracture in a bone;

FIG. 148 illustrates a triangulation device used to repair a fracturedbone;

FIG. 149 shows multiple thermoplastic fasteners and an anchor used tofix a broken bone;

FIGS. 150A and 150B illustrate the welding of a thermoplastic componentto a non-thermoplastic component;

FIGS. 151A and 151B show a thermoplastic component welded into a cavityof a non-thermoplastic component;

FIG. 152 shows dynamic spinal stabilization using thermoplastics andcables;

FIG. 153 illustrates thermal welding of a disc replacement component;

FIG. 154 shows rigid and one-plane stabilization of the spine;

FIG. 155 is a perspective view of a vertebral body replacement implantthat may be assembled using thermal bonding;

FIGS. 156A-156F illustrate various embodiments of thermoplasticfasteners;

FIG. 157 shows knee repair and stabilization using the surgical weldingsystem of the present invention;

FIG. 158 is a perspective view of a total knee replacement implanthaving thermoplastic stabilizers welded thereon;

FIG. 159 illustrates implant tethering using thermoplastics;

FIGS. 160A-160C show various embodiments of heat shrinkable implantpouches;

FIG. 161 illustrates thermal bonding of acetabulum implants;

FIG. 162 shows thermoplastic material functioning as a bearing surface;and

FIG. 163 illustrates thermoplastic material used to bond bearing surfacematerial in a hip replacement implant.

FIGS. 164 and 165 illustrate an exemplary embodiment of a fastenerassembly;

FIGS. 166-168 illustrate different views of the fastener cap of thefastener assembly of FIGS. 164 and 165;

FIGS. 169-171 illustrate different views of the anchor of the fastenerassembly of FIGS. 164 and 165;

FIGS. 172-173 illustrate another embodiment of the invention forfastening an implant or tissue material to bone;

FIG. 174 illustrates an embodiment of the invention for fasteningmaterial to bone;

FIGS. 175-177 illustrate different embodiments for fastening a tack to arod disposed in a cavity;

FIGS. 178 and 179 illustrate an embodiment using a plurality of tackssecured to a rod disposed in a cavity;

FIGS. 180-182 illustrate further embodiments of fasteners;

FIGS. 183 and 184 illustrate variations in notched rod configurations;

FIGS. 185-190 illustrate an embodiment of the invention having a plateand weldable fasteners;

FIGS. 191-194 illustrate another embodiment of a fastener;

FIGS. 195-196 illustrate an embodiment of the invention having afastener and rod disposed in a cavity;

FIGS. 197 and 198 illustrate a knotless suture fixation system;

FIGS. 199A and 199B illustrate ultrasonic systems with curved orflexible end effectors; and

FIGS. 200A and 200B schematically illustrate the radial deformation orcollapse of the fastener after the application of ultrasonic energy.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, the invention relates to devices and methods thathelp stabilize tissue or implanted materials in a patient's body. Aswill be explained in greater detail below, the invention can be utilizedin several ways to achieve different desired results, including thefixation of two different tissue types, the fixation of an implant totissue, or the fixation of an implant to another implant.

The methods and devices disclosed herein may be used in conjunction withany surgical procedure of the body. The fastening and repair of tissueor an implant may be performed in connection with surgery of a joint,bone, muscle, ligament, tendon, cartilage, capsule, organ, skin, nerve,vessel, or other body parts. For example, tissue may be repaired duringintervertebral disc surgery, knee surgery, hip surgery, organ transplantsurgery, bariatric surgery, spinal surgery, anterior cruciate ligament(ACL) surgery, tendon-ligament surgery, rotator cuff surgery, capsulerepair surgery, fractured bone surgery, pelvic fracture surgery,avulsion fragment surgery, shoulder surgery, hernia repair surgery, andsurgery of an intrasubstance ligament tear, annulus fibrosis, fascialata, flexor tendons, etc.

Also, an implant may be inserted within the body and fastened to tissuewith the present invention. Such implant insertion procedures include,but are not limited to, partial or total knee replacement surgery, hipreplacement surgery, shoulder replacement surgery, bone fixationsurgery, etc. The implant may be an organ, partial organ grafts, tissuegraft material (autogenic, allogenic, xenogenic, or synthetic),collagen, a malleable implant like a sponge, mesh, bag/sac/pouch,collagen, or gelatin, or a rigid implant made of metal, polymer,composite, or ceramic. Other implants include breast implants,biodegradable plates, porcine or bovine patches, metallic fasteners,compliant bearing for medial compartment of the knee, nucleus pulposusprosthetic, stent, tissue graft, tissue scaffold, biodegradable collagenscaffold, and polymeric or other biocompatible scaffold. The scaffoldmay include fetal cells, stem cells, embryonic cells, enzymes, andproteins.

Thus, the invention may be utilized as a trauma welding system for thestabilization of damaged tissue, such as fractured bones. In thisapplication, the system may include devices and methods forintracorporeal bonding of thermoplastic material. An energy source canbe used to weld the material in place. The energy source may beresistive heating, radiofrequency, ultrasound (vibratory), microwave,laser, electromagnetic, electro shockwave therapy, plasma energy (hot orcold), and other suitable sources. Likewise, the energy source mayenable a portion of material to be foamed or expanded such that twocomponents of the welding system are secured together. Other energysources, surgical procedures, and medical instruments which may be usedwith the present invention are disclosed in U.S. Provisional PatentApplications Nos. 60/765,857 filed Feb. 7, 2006; 60/784,186 filed Mar.21, 2006; and 60/810,080 filed Jun. 1, 2006, as well as U.S. patentapplication Ser. No. 11/416,618 filed May 3, 2006. The contents of thesedocuments are incorporated by reference herein in their entirety.

The trauma welding system and other embodiments of the present inventioncontemplates the use of any biocompatible material weldable within thehuman body. The materials used may include, but are not limited to,degradable, biodegradable, bioerodible, bioabsorbable, mechanicallyexpandable, hydrophilic, bendable, deformable, malleable, riveting,threaded, toggling, barded, bubbled, laminated, coated, blocking,pneumatic, one-piece, multi-component, solid, hollow, polygon-shaped,pointed, self-introducing, and combinations thereof. Also, the devicesmay include, but are not limited to, metallic material, polymericmaterial, ceramic material, composite material, body tissue, synthetictissue, hydrophilic material, expandable material, compressiblematerial, heat bondable material, and combinations thereof.

Preferably, this material can become gel-like, tacky, or soft with theapplication of energy. The energy source and the technique used to weldthe material within the body can be selected to minimize or avoid damageto surrounding body tissue. Exemplary materials that may be used mayinclude polymers, ceramics, composites, and metals, although othermaterials may also be suitable for use with the invel ltion. While thepresent invention contemplates the use of any of these materials in anyof the following embodiments, polymeric material is used in thefollowing examples and description simply to illustrate how theinvention may be used.

Generally, there are two types of polymers: thermoset and thermoplastic.Thermoplastics may be used with the present invention because they canbe softened, reheated, molded and remolded. Thermoplastics are generallyclassified as either amorphous or semi crystalline. Some semicrystalline polymers have some amorphous structure while other semicrystalline polymers may be more crystalline than others. Examples ofamorphous polymers are poly carbonate (LEXAN), polystyrene, polysulfone(ULDALL), and acrylics polycarbonate (ABS and styrenes). Examples ofsemi crystalline polymers include acetyl (DELRIN), nylon, polyester,polyethylene, polyether ether ketone, poly propylene, polyvinylchloride(PVC), and Caprolactam. Biodegradable semi crystalline polymers mayinclude polylactic acid and polyglycolic acid. Copolymers of PGA and PLAmay also be used. These copolymers may ultrasonically bond better thanpure PGA and PLA. Other polymers which may be used with the presentinvention, either as a thermoplastic or non-thermoplastic, arepolyethylene glycol (PEG)-copolymers and D,L-lactide-co-glycolidepolyesters.

Some semi crystalline materials have an amorphous structure or anamorphous region within them. These materials are particularly suitablefor surgical welding, especially ultrasonic welding. Examples of suchmaterials include PEEK and PEAK. With these special semi crystallinematerials, the amorphous content of the polymer makes the material moreconducive to ultrasonic welding, and therefore a better bond isachieved. Also, a lower amount of energy is needed to bond thesematerials.

The semi crystalline materials without an amorphous structure or regionhave a rigid or fixed melting point. A high level of energy it requiredto breakdown the crystalline structure before the melting occurs. Oncethe melting starts, the material very rapidly moves through thetransition area from a solid to a flowable substance, i.e. a liquid.Also, the molecular structure of semi crystalline materials absorbsvibrational energy making it more difficult to transmit the vibrationalenergy from an energy producing instrument to the interface of the partsbeing welded. For example, polylactic acid reaches its melting point andgoes through its transition region rapidly which causes it to flow inthe tissue. This rapid heating and complete, or nearly complete, meltingof the material weakens the overall structure and causes tissuenecrosis. When this material is used in surgical screws, plates, rods,etc., care must be taken to avoid over melting and weakening of theimplant. The temperature, time, and pressure must be closely monitoredand controlled with semi crystalline materials or the implant will fail.

The polymers used in the present invention, such as PEEK and PLLA, haverandomly arranged molecules allowing vibrational energy to pass throughthe material with little attenuation. As such, the material requiresrelatively little ultrasonic energy to make the material soften andbecome tacky. This small amount of energy or heat needed to bond PEEKand PLLA helps avoid or minimize the likelihood of tissue necrosis. Thetransition period is longer in duration and therefore, when applyingenergy, the material gradually softens, passing from a rigid statethrough a transition state to a rubbery state and then to a flowablegel-like state. The amorphous features of these materials make themultrasonically weldable with lower temperature and better weldingpoints. To bond these materials, the true melting point does not need tobe reached or exceeded, so there is less risk to surrounding bodytissue. PEEK and PLLA are also useful with the welding system of thepresent invention because it has a modulus of elasticity very close tobone. Also, some grades of PEEK and PLLA have a hydrophilic componentwhich permits hydrophilic interlocking when placed in the body.

The temperature, time, pressure, and other parameters of the weldingprocess may be closely monitored and controlled to achieve an effectiveweld. Also, because the material does not substantially melt (only thewelding region softens and becomes tacky) the holding strength of thethermoplastic during and after welding is not jeopardized. That is, afastener made of a thermoplastic which melts, like those in the priorart, cannot maintain a compressive force against a component or implantduring the welding process. This is because the material of the fastenerbecomes liquefied, and a fastener in liquid form cannot maintain acompressive or tension force. The present invention contemplatesimplants made of PEEK or PLLA which bond by softening or making tackythe polymer material at the bonding region. The remaining PEEK or PLLAmaterial does not flow and therefore retains its ability to maintain acompression or tension force.

When bonding two thermoplastic components together, it is optimal thatthe components be chemically compatible to create a molecular bond.Similar thermoplastics may be compatible if their melt temperature iswithin about 6 degrees Celsius or if they have similar molecularstructures. Generally, amorphous polymers may be welded to each other.In the present invention, PEEK may be bonded to PEEK. Biodegradablepolymers may be bonded to biodegradable polymers. Biostable polymers maybe bonded to biostable polymers. Biodegradable polymers may be bonded tobiostable polymers.

When two dissimilar materials need to be bonded together, the weldingmay be performed outside the body, such as during the manufacturingprocess or within the operating room. This is done to avoid damage tosurrounding tissue caused by the heat required to weld the dissimilarmaterials to each other. Then, once implanted, further welding may bedone within the body to bond like thermoplastics creating the desiredimplant configuration. For example, a spacer made of PEEK may be bondedto a metallic implant outside the body. The spacer and implant may beplaced in the body, and the PEEK may be welded ‘With another PEEKelement inside the body so that there is a PEEK to PEEK bond. The metalimplant may be the load bearing surface or the bearing point, while thePEEK to PEEK weld provides for the fastening and stabilization of theimplant.

There are several factors that effect welding of thermoplasticmaterials. One is hydroscopicity, the tendency of a material to absorbmoisture. If too much fluid gets between the welded parts it candecrease the bond or create a foam which prevents proper bonding of thematerials. Therefore, the welding of thermoplastics may be performedunder vacuum/suction, or a hermetic seal may be placed around thethermoplastic during the welding process. Also, the welding may beperformed using a cannula which prevents fluid from entering the weldingarea. Furthermore, pressure, such as air pressure or compression force,may be applied during welding to prevent entry of moisture or liquid.

In addition to or in place of reducing moisture from the welding area,certain agents can be used to aid in the bonding process. Such agentsmay include filler material, glass filler, glass fiber, talc, andcarbon. The agents may be placed at the bond site as a temporary weldingenhancement means or may be a permanent agent to enhance the bonding.For example, the agent may be placed within the bonding region of PEEKor PLLA. The agent may be left in place to bond or could be removed. Itis contemplated that any amount of agent may be used to enhance the bondstrength of the thermoplastics. In an exemplary embodiment, the amountof agent may be about 10 to 20 percent.

Moisture may further be eliminated or prevented from entering thethermoplastic material through the use of desiccants. Desiccants may beadded prior to or during the welding process. Also, the thermoplasticmaterial may be stored using desiccant material to prevent change inthermal properties. It is contemplated that this moisture reducing meansmay be applied to any polymeric material.

Another factor effecting the welding of thermoplastic material ispigments, especially white and black coloring. In many materials used inmedical applications, white pigment is added to the polymer to make itappear sterile. Some pigments negatively affect the weldingcharacteristics of the material. In the present invention, pigment-freethermoplastics, such as PEEK, are thermally welded for proper bonding ofthe material.

Mold release agents also affect the welding properties ofthermoplastics. Polymeric components are usually formed in a mold tocreate a desired configuration. The component is easily removed from themold because a release agent is placed between the mold and polymer.These agents, lubricants, plasticizers, and flame retardants cannegatively affect the bonding ability of the polymer. Thus, it ispreferred in the present invention that PEEK, PLLA, and otherthermoplastics used for welding are substantially free of thesesubstances.

In addition to avoiding release agents, pigments, and moisture, thebonding of thermoplastic materials may be further enhanced by addingminute metallic material to the polymer. The metallic material may bemetal flakes or metal dust. Examples of such metal include ironparticles, chromium, cobalt, or other suitable metals. The metal may beembedded within the polymeric material to enhance the thermalproperties. Alternatively, or in addition, the metal may be applied tothe bonding surfaces of the polymeric material. Energy applied to thepolymer would heat both the polymeric and metallic material providing afaster and more uniform weld. It is contemplated that glass fillers,carbon fillers, talc, or combination thereof may also be used inaddition to or in lieu of the metallic material.

Other factors affecting the welding of thermoplastics include size,thickness, surface geometry, material properties of the thermoplastic,and the type of host tissue involved in the weld, i.e. soft, hard, dry,wet, or moist tissue. These and other factors are explained in moredetail with reference to FIG. 5.

Furthermore, how the thermoplastic is welded is an importantcharacteristic of obtaining a robust thermal bond. The type of energyused is one way to control the welding process. As previously mentioned,various energy sources may be used to weld polymers. In an exemplaryembodiment and as used primarily throughout the invention, ultrasoundenergy is used to create vibrations within the polymeric materialthereby exciting and heating the molecules to transition to a tackystate. Two or more different types of energy may also be used. Forexample, ultrasound may be used to weld a polymeric component to anothercomponent, while resistive heating may be used to contour the surface orchange the geometry of the materials. The surface of the component maybe smoothed out or sculpted using resistive heating.

The intensity and duration of the energy source impacts the quality ofthe weld. For instance, the amount of power or watts used affects theweld. Therefore, the watts may be controlled by the operator dependingon the component to be welded. A switch, dial, or other control may beplaced in connection with the energy source to vary the intensity of theenergy applied to the weld. For example, the amount of current suppliedto the instrument may be varied or controlled. In an exemplaryembodiment, the ultrasound power may be varied, for example, between 80and 100 watts. The amount of time the energy is applied affects the weldas well. The time may be varied from milliseconds to hundredths ofseconds to actual seconds depending on the desired weld. Thus,controlling the time of exposure to the energy source can be used tolimit the amount and the degree of thermoplastic material which softensand becomes tacky. In an exemplary embodiment, energy may be appliedfrom 0.1 seconds to 3 seconds, such as approximately 0.3 seconds. Incase of RF and ultrasonic energy, the wavelength of the energy may bevaried to affect the softening or melting of the thermoplastic. It isalso contemplated that the amount of time that energy is applied may becontrolled not only by the operator but also via radiofrequency,optical, radiowave, etc. A computer or other microprocessor may sendsignals to the energy emitter to turn the energy on and off.

Pulsing of the energy source may likewise be used to intermittentlyapply energy to the weld site or to vary characteristics of the energysource over time, such as the power, frequency, or pressure, to enhancebonding and avoid tissue necrosis. That is, the energy may be emitted,then relaxed, then emitted, etc.

Controlling the pressure applied to the thermoplastic material also maybe used to affect the welding process. During welding, a handpiece, ananvil, a horn, end effector, or combinations thereof may be used toapply controlled force against the welded component. Alter welding,while the welded material is cooling, the force may continue to beapplied to ensure proper bonding of the materials. The handpiece, anvil,horn, and end effector may be made of aluminum, titanium, or othersuitable material. Also, the pressure may be varied, increased ordecreased, during the welding process. In an exemplary embodiment, thepressure may be applied by the operator or may be applied with a spring.A sensor, spring, and/or piezoelectric device may be used to monitor andcontrol the amount of pressure applied. In another exemplary embodiment,the welding horn may apply ultrasound energy and pressure to a polymericimplant being attached to bone. The bone may act as the anvileliminating the need for an anvil instrument. Also, a hard implant oranother polymeric material may function as the anvil.

Furthermore, the placement of the energy source on the thermoplasticaffects the weld. The energy may be applied to one side of the polymer,through the center of the polymer, to two or more sides of the polymer,or to generally the outer surface of the polymer.

Controlling collapse is another factor in achieving an effectivethermoplastic weld. For instance, the weld time and material collapsemay be monitored to ensure a proper weld. A measurement of the change ofthe material being welded may be made to determine when bonding iscomplete. This may be accomplished by using micro-switches to provideprecise, binary control of the mold. Also, by using a linear variabledisplacement transducer (LVDT), the control system can monitor the weldmore precisely. Because a LVDT translates position to voltage, the weldprofile can be dynamically controlled. For example, the initial energydelivered can be a higher wattage, then when the material starts tocollapse the amplitude of the wave can be decreased.

By being able to monitor the position of the collapse, different weldprofiles can be programmed into the system. In addition, to control howfar the material collapses on the anchor during a weld, a combination ofweld current and time preset in the generator control system could beused. This can also be coupled with a defined force applied during theweld. Furthermore, collapse may be controlled or monitored through theuse of a mechanical stop on the fixation device itself or on the weldinginstrumentation. The mechanical stop would prevent collapse after apredetermined point. It is also contemplated that the collapse could bemonitored by other methods such as optics, laser, or even a hall-effectsensor.

All of the above-mentioned welding parameters may be monitored andcontrolled by a computer. The discussion relating to FIGS. 5-8, amongothers, illustrate instruments that may be used for controlling weldparameters. Feedback may be provided by the computer to vary, start, andstop the various parameters of welding. The feedback and control of thecomputer may be programmed based on the type of polymer being welded andthe type of material the polymer is being welded to. For example, forPEEK to PEEK welds, the computer may apply a set of parameters (time,power, pressure, frequency, wavelength, etc.) to achieve a desired oreffective weld. Other parameters may be established or preset for otherpolymers, other weld materials, or for welding dissimilar materials.

Any known energy emitting instrument may be used with the surgicalwelding system of the present invention. The instrument may produceenergy such as resistive heating; radiofrequency, ultrasound(vibratory), microwave, laser, electromagnetic, electro shockwavetherapy, plasma energy (hot or cold), and other suitable energy. FIG. 1illustrates an exemplary welding instrument 100 that may be used withthe present invention. The welding instrument 100 may be an ultrasonichandpiece with a sheath 102 to cover and protect the end effector 104and hold a fastener. As will be discussed in greater detail below, thewelding instrument may be used to weld a cap of an implanted device toan anchor, or likewise may be used to weld other components together.

The sheath 102 may have a small counter bore at its tip to cover aportion of the cap. There also may be a bushing at a nodal point of theultrasonic signal to prevent the end effector 104 from contacting thesheath 102. The tip of the end effector 104 has a small post 106sticking out of the welding face which presses into a bore in the cap ofthe fastener. This can help align the fastener post into the anchor boreand keep the cap tight against the end effector face. The end effector104 may be removable to allow it to be replaced or cleaned afterwelding.

The post 106 on the end effector 104 may be threaded or have a Morsetaper to mate with the cap. Alternatively, the end effector 104 has abore that the top of the cap mates into. The mating of the componentscould also be by threads or a Morse taper along with a straight post.Furthermore, the post could be roughened on the outside surface forbetter adhesion.

Another exemplary instrument is illustrated in FIGS. 2A and 2B. A smallcartridge heater 110 may be used to deliver thermal energy. The heater110 may be a SUNROD ⅛ inch cartridge heater. To prevent heat build up ofthe outside shaft 112, an insulating region 114 may be formed betweenthe welding horn 116 and the shaft 112. In FIG. 2A, four set screws 118are used to create the insulating region 114, which in this example isan air barrier, while in FIG. 2B, a single set screw 118 is used.

Referring to FIGS. 3A-3K, energy emitting instruments may includevarious horn or end effector configurations. It has been discovered thatfor a fixed set of welding parameters (energy, power, time, etc.), thewelding or bond characteristics can be varied depending on theconfigurations of the horn or end effector. For example, if extension122A is made longer or the angle of the tip is changed, the weld or bondcreated can be adjusted. In FIG. 3A, the horn 120A emits energy to thetop surface of the implant as well as the central core via an elongateextension 122A. The horn 120B of FIG. 3B is recessed to hold thethermoplastic implant during welding. In FIG. 3C, the horn 120C isconcave to provide a rounded surface to the implant after welding. Thehorn 120D of FIG. 3D is concave and includes a central extension 122D todeliver energy throughout the implant. In FIG. 3E, the horn 120Eincludes a spike 124E which may be disposed within an implant. The horn120F of FIG. 3F includes a threaded pin 126F which may be received by abore in the implant. In FIG. 3G, the horn 120G includes dual spikes124G. The distal portion of the horn 120H of FIG. 3H may be dimensionedto fit within the thermoplastic implant. In FIG. 3I, a sleeve 128I isdisposed about the horn 120I and implant. A side-weld horn 120J is shownin FIG. 3J. In FIG. 3K, a dual horn welder 120K is used tosimultaneously weld two fasteners 130.

In FIGS. 4A-4C, a welding instrument 140 is shown which includes threedifferent horn or end effector configurations in one design. Theinstrument 140 can be configured to have a bonding-surface horn (FIG.4A), a welding horn (FIG. 4B), and a contouring horn (FIG. 4C). FIG. 4Ashows the instrument 140 in the bonding-surface horn configuration. Thecenter shaft 142 is extended distally from the instrument 140, and theouter shaft 144 which slides over the center shaft 142 is also extendeddistally. In FIG. 4B the outer shaft 144 has been retracted into thewelding instrument, leaving only the center shaft 142 extended. In thisposition, the instrument 140 is in the welding horn configuration.Finally, FIG. 4C shows both the center and outer shafts 142 and 144retracted into the instrument. The sheath 146 which surrounds theinstrument 140 has also been retracted. In this position, the instrument140 is in the contouring horn configuration. The distal surface 148 ofthe contouring horn may be used to reshape a thermoplastic implant, suchas the head of a fastener.

In use, the instrument of FIGS. 4A-4C may be reconfigured quickly by theoperator during a welding operation. In the bonding-surfaceconfiguration, the instrument is positioned such that the distal portionof the extended center and outer shafts 142, 144 come in contact with athermoplastic component or implant. Energy, such as ultrasonic energy,may be emitted from the center and outer shafts to create a roughenedsurface on the implant, to create an indentation or blind hole in theimplant, or to create a through hole in the implant. The type offixation desired and the intended fastener to be used will determine howdeep the bonding-surface horn should be moved into the implant. With thebonding surface formed, the outer shaft 144 is retracted into theinstrument (FIG. 4B).

The distal portion of a fastener may be placed in or on the bondingsurface of the implant, and the end effector may be placed on thefastener with the center shaft extending into a bore in the fastener.Using the desired welding parameters, the operator emits ultrasonicenergy from the end effector to bond the fastener to the implant. Oncewelded, the fastener may be contoured or reshaped or resized with thecontouring horn of the instrument by retracting the center shaft andoptionally retracting the sheath around the instrument (FIG. 4C).

As previously mentioned, monitoring and controlling the weldingparameters ensures proper bonding of thermoplastics. FIG. 5 illustratesthe various parameters that may be monitored and controlled for thetrauma welding system of the present invention. The parameters include,but are not limited to, the type of energy to emit, type ofthermoplastic material, the size and configuration of the implant, thethickness of the implant, implant surface geometry, the aqueousenvironment, weld time, weld power, frequency and wavelength of theenergy, amount of pressure applied to the implant during and afterwelding, the geometry of the weld horn, the impedance of the weldinghorn, the density of the implant, the amount of collapse of thethermoplastic material, the depth into tissue the implant is to beinserted, and the type and amount of any therapeutic agent that may bedelivered.

FIG. 6 shows a manual welding control box 150. A surgeon determines theoptimum or desired welding parameters and may then enter them into thecontrol box 150 prior to or during welding. In FIG. 7, an automaticcontrol box 152 may be provided with pre-set weld parameters. Forexample, preset 1 may be for implant A which has a known material, size,etc. to be welded in a dry environment. Preset 2 may be for implant A ina moist environment. Preset 3 may be for implant A in a wet environment.Preset 4 may be for implant B using energy source X. Preset 5 may be forimplant C using energy source Y. Preset 6 may be implant D using energysource Z. It is contemplated that any combination of weld parameters maybe pre-set into the control box.

The control box 154 of FIG. 8A is automatic. A sensor on the endeffecter 156 determines the weld parameters when the horn is placedadjacent the thermoplastic material. The sensor 156 picks up materialtype, humidity of the environment, and any other parameter, then sendsthe data to the control box. The control box 154 automatically selectsthe energy source, time, wattage, and any other parameters. FIG. 8Billustrates an ultrasonic energy control box which may be used with thesurgical welding systems of the present invention.

The exemplary energy control units described herein may be used toselect and vary any of the welding parameters. In FIG. 8C for example,the power or wattage of the welding horn is varied over time. During afirst period of welding, a large amount of energy is delivered toovercome heat sink. In the second period, the energy is reduced. In asubsequent period, the energy is maintained at an appropriate level tothermal weld an implant.

Other variations of the use of a control box may likewise be used. Forinstance, a computer may be used to query or receive data about thesurgical procedure. The physician may enter an implant manufacturer, forinstance, and then select or enter an implant model, size, etc. Based onthe entered information, the computer may assist the physician byinstructing which energy source(s), weld horns, or other parameters maybe recommended for the procedure. While the control box or computer mayautomatically select and apply a weld profile based on expected inputweld parameters, the control box or computer may also allow a physicianto alter or override the expected input or otherwise select a differentweld profile. The ability to allow varying degrees of manual control ofthe welding instrument may also be provided.

The exemplary energy control units previously described may be used toselect and vary any of the welding parameters. For example, the power orwattage of the welding horn may be varied over time. During a firstperiod of welding, a large amount of energy may be delivered to overcomeheat sink. In the second period, the energy may be reduced. In asubsequent period, the energy may be maintained at an appropriate levelto thermal weld an implant.

To help ensure a properly executed weld, the welding instrument of thepresent invention may provide a positive feedback system. One way toprovide user feedback is by measuring and controlling the impedance(resistance) of the end effector or weld horn. This feedback system isbased on the fact that the load placed on the end effector affects theimpedance of the system. That is, the pressure put on the end effectorby the object to be welded changes the resistance of the end effector.To determine the hand piece or end effector impedance, the drive voltageand current through the end effector may be monitored during the weld.By using Ohm's Law V=IR, the impedance, R, may be calculated from thevoltage, V, and current, I.

FIG. 9 illustrates one method of ensuring a consistent or desired weld.By first transmitting low power ultrasonic signal through the endeffector, the impedance of the handpiece can be measured with nopressure. This establishes a baseline impedance for the end effector.Then, the end effector may be subjected to known pressures and thevoltage and current may be measured to calculate the impedance for eachpressure. Therefore, when a surgeon or other operator applies pressurefrom the end effector to a thermoplastic implant to be welded, theactual amount of pressure can be fed back to the operator because thepressure can be correlated to a known impedance. The surgeon mayincrease or decrease the pressure on the end effector until the desiredpressure is achieved. In one embodiment, the welding instrument mayprovide audible and/or visual signals that indicate when a surgeon isapplying too much, too little, or an adequate amount of pressure. Withthe correct pressure applied, the surgeon may activate the handpiece andemit ultrasonic energy in accordance with the calculated weld profile.

In another exemplary embodiment for providing positive feedback, thepressure and impedance of the end effector may be monitored throughoutthe weld profile. In the previously described method, the properpressure based on impedance was achieved by the surgeon using a lowpower signal, and then the ultrasonic energy was emitted from welding.In this method, the pressure and impedance is measured during the weld.When pressure on the end effector is applied and the weld is started,for example by a hand control or footswitch, the current may be measuredand the impedance calculated by a microprocessor. When the impedance istoo high or too low or outside an acceptable range indicating anincorrect applied pressure, the microprocessor may send an audible orvisual signal to the surgeon.

Alternatively, or in addition to the signal, the microprocessor can stopenergy emission until the correct pressure and impedance is achieved,then the welding may be resumed either automatically by themicroprocessor or manually by the surgeon. If inadequate pressure isbeing exerted, the welding instrument may operate in a pulse mode tomaintain material in a near-weld state. This may allow the welding tomore rapidly continue when adequate pressure is once again beingapplied.

Referring FIG. 10, because the drive signal is sinusoidal, V_(monitor)and V_(current) must be sampled at a rate that is at least twice thefrequency of the ultrasonic waveform. For example, if the waveform is a41 kHz sinusoid, then samples may be taken at 328 kHz, or one sampleevery 3 μs. In this example, solving for the impedance, the handpiecewould be 500Ω.

Also, by monitoring handpiece impedance, changes to the weldenvironment, such as moisture, ambient temperature, aqueous conditions,etc., may be automatically compensated for by adjusting the drivewaveform of the ultrasonic energy. For example, if for a certainmaterial it is determined that 80 W of power is required for a 400 msperiod to achieve a consistent weld, then the waveform can be adjustedto ensure that this amount of energy is constantly delivered. Power iscalculated using P=IV, but because the signal from the waveform issinusoidal, the root mean square (RMS) voltage as V=(1/√2)A must beused.

As the impedance, R, of the handpiece changes, the total power deliveredalso changes. By increasing or decreasing the drive voltage tocompensate for the change in the impedance, a constant power can bedelivered.

In another exemplary method, seat collapse may be monitored, such as bythe use of SONAR. Seat collapse is the distance a thermoplastic fasteneror implant shrinks in height when ultrasonic energy is applied.Generally, thermoplastic fasteners may shrink about 20 percent in heightand increase 30 percent in width when welded. For fasteners having twopieces, such as a cap and an anchor, the attenuation of the reflectedultrasonic waves changes as the two piece fastener becomes one piece.This change in attenuation may be monitored to alert the surgeon oroperator when the weld is complete. Furthermore, an ultrasonictransducer could be used in conjunction with the end effector to detectthe change in acoustic impedance/attenuation of the weld site. Thissignal may be monitored by a microprocessor/controller or data signalprocessor (DSP) and data may be automatically interpreted to indicatewhether the weld was successful.

Another way of providing feedback of an effective weld is to monitor theEddy currents created by the movement of the end effector. As the endeffector vibrates, the linear motion creates a change in the magneticfield. By monitoring the travel of the end effector, the amount ofcollapse can be determined.

It is also contemplated that the material being welded may betranslucent or transparent, and a visual indicator within the materialcould indicate when the weld is complete. For example, a pigment, dye,or other substance may be impregnated into the thermoplastic which whensubjected to ultrasonic energy the pigment or dye would be releasedindicating that the weld is complete. Alternatively, the material of thethermoplastic may have the characteristic of changing color as heat,vibrations, or ultrasonic energy is applied for a predetermined time anda predetermined frequency and wattage.

The previously described methods for providing positive feedback to theweld operator included the use of measurements and/or computers. Anotherpositive feedback system is provided which relies on physical force.When two objects are fastened to each other, it is common for thetechnician or mechanic to pull or tug on the assembly to ensure theparts are securely fastened. This common technique may apply to thethermoplastic welding system of the present invention. Once a fasteneror other implant is ultrasonically welded, the surgeon can apply a quicktug on the assembly to verify the weld was completed as intended.

FIGS. 11A and 11B illustrate a feedback instrument 160 for performingsuch a physical positive feedback cheek. An end effector 162 includes apost 164 which emits ultrasonic energy. A thermoplastic fastener 166 isplaced on the end effector 162 with the post 164 in a bore or receptacle168 of the fastener 166. After emitting ultrasonic energy and weldingthe fastener to an implant or tissue, the surgeon may actuate a biasingprong or prongs 170 from the post 164 of the end effector while the post164 is still in the fastener 166. In a stored configuration, the prongs170 are positioned within the post 164. In a deployed configuration, theprongs 170 extend radially from the post 164 by the activation of ahandle, switch, or button. The extended prongs 170 dig slightly into thematerial of the fastener 166 so that the surgeon may now pull or tug onthe instrument 160 proximally to verify that the fastener 166 issecurely welded in place. Additionally, the prongs 170 and/or post 164may include a strain gauge or other force measuring device to measureand display to the surgeon how many pounds of pull strength is being puton the fastener.

Some exemplary fasteners of the present invention are illustrated inFIGS. 12A-12F. The fastener 180A of FIG. 12A is made entirely of athermoplastic material such as PEEK. In FIG. 12B, the fastener 180Bincludes one type of thermoplastic material in the lid 182 and adifferent type of thermoplastic material in the post 184. Each materialmay have different welding properties. FIG. 12C shows a fastener 180Cwith only a proximal portion 186 made of PEEK, while FIG. 12Dillustrates a fastener 180D with only a distal portion 188 made of PEEK.In FIG. 12E, the fastener 180E includes a rigid metallic core 190 whichis enclosed by a thermoplastic 192. The fastener 180F of FIG. 12F has apolymeric core 194 surrounded by PEEK 196. Although not illustrated inthese examples, the fasteners may include a central bore for receivingthe post of the end effector.

FIGS. 13A and 13B show a bone plate or rod 200 for use with the traumawelding system of the present invention. Plate or rod 200 may be free ofholes or may include pre-drilled thru-holes 202 or edge-holes 204 forpositioning fasteners therethrough. The holes may be formed by themanufacturer at the factory or by the surgeon in the operating room. Theplate or rod 200 may include a roughened surface 206 in some areas orover the entire surface. The roughened areas 206 provide a bondingregion for fasteners or other thermoplastic implants. Additionally, theplate 200 may include blind holes 208 for securing a fastener therein.The blind hole 208 is an indentation in the surface of the plate 200which extends only partially into the plate 200. The thru-hole,roughened area, and blind hole are bonding regions. In FIG. 13B, athermoplastic fastener 210 is positioned in an edge-hole 204 of theplate 200. The distal end of the fastener 210 may be seated in anotherimplant or tissue, such as bone. Because the plate includes theedge-hole, the fastener may be first at least partially implanted, thenthe edge-hole of the plate may be positioned around the fastener. Onceproperly aligned, the plate 200 and fastener 210 may be welded togetherand the proximal end or head 212 of the fastener 210 may be contoured asdesired.

In addition to the fasteners described in FIGS. 12A-12F, other fastenerconfigurations are illustrated FIGS. 14A-14D. In FIG. 14A, the fastener220A includes a mechanical locking mechanism in addition to thermalbonding. The fastener 220A includes thermoplastic material and includeshelical threads 222 disposed on the outer surface thereof. In FIG. 14B,the fastener 220B includes longitudinally extending edges 224. Theselongitudinal edges 224 may function as energy directors to focus theultrasonic energy along the edges providing a secure bond to tissue oran implant. FIG. 14C illustrates a wedge shaped or Morse taper fastener220C. The fastener 220D of FIG. 14D includes an angled shoulder 226which may be seated against an implant or tissue and thermally bonded inplace.

The combination of thermoplastic material and ultrasonic energy of thepresent invention is advantageous for modifying and preparing implantswhile the implants are in the body. In FIG. 15A, a plate 230 may bepositioned against bone to stabilize a fractured bone or damagedvertebrae. With the plate 230 in place, a notch or nest 232 may be cutusing heat energy or other mechanical means such as a drill or saw. Thenotches 232 are dimensioned and configured to receive a rod 234 orfastener. Therefore, implanting and thermally bonding a rod in the notch232 creates a desired geometric shape with the plate 230 and rod 234extending generally perpendicular to each other. In this configuration,the assembly may be used to stabilize the spinal column or may functionas a combination internal-external fracture bone stabilizer. In thelatter case, a first plate may be positioned against the fractured bone,while an exterior plate may be bonded to one or more rods extending fromthe notches of the first plate. The first plate provides internalfixation, and the exterior plate provides external fixation. The rodsbonded between the two plates function as pins passing through the skinand other soft tissue. To further secure a rod within the notch of theplate, a fastener 236 may be inserted as shown in FIG. 15B. The plate230, rod 234, and fastener 236 may be thermally welded at severalbonding regions 238.

The thermoplastic fasteners of the present invention may also beexpandable. FIGS. 16A and 16B illustrate one embodiment of a fastener240 which includes a cap 242 and an expandable anchor 244. The anchor244 is generally V-shaped or conical, convex shaped. The anchor 244 mayinclude a tissue-piercing distal tip 246 to penetrate into and throughtissue and implants, such as plates or rods. As seen in FIG. 16A, theanchor 244 includes a bore 248 that may taper down from the proximal endto the distal end. The bore 248 is dimensioned and configured to expandwhen receiving the post 250 of the cap 242. Therefore, the post 250tapers from the proximal end or head down to the distal tip. The distaltip of the post 250 may also include a tissue-piercing end. In anexemplary method of use, the expandable anchor 244 is inserted through alayer of tissue 252. A plate or other implant 254 (or other tissue) isplaced adjacent the tissue 252. The post 250 of the cap 242 is moveddistally through the plate 254 and tissue 252 and into the bore 248 ofthe anchor 244 causing the anchor to expand outwardly or radially, asshown in FIG. 16B. With the head 256 of the cap 242 pressing the plate254 against the tissue 252, the cap 242 is ultrasonically welded to theanchor 244. The anchor is prevented from being removed from the tissuebecause the expanded wall portions of the anchor contact the undersideof the tissue.

FIGS. 17A and 17B illustrate another expandable fastener 260 embodiment.The principle of insertion and expansion are similar to the fastener ofFIGS. 16A and 16B. However, in this embodiment, the anchor 262 isgenerally cylindrical in shape. The anchor 262 has a cylindrical boretherein. The cap 264 includes a post 266 which is generally cylindricaland has a widened portion disposed between a proximal portion and adistal portion. The diameter of the distal portion of the post 266 isconfigured for initial insertion in the bore 268 of the expandableanchor 262. The diameter of the widened portion is configured such thatit expands the walls of the anchor 262 radially outward as the cap 264is moved distally into the anchor 262. In a seated configuration, thecap 264 is ultrasonically welded to the anchor 262 and the head 270 ofthe cap 264 holds a plate or tissue 272 against lower tissue 274. Theexpanded walls of the anchor contact the lower tissue preventing thefastener from being pulled out.

Referring to FIGS. 18A and 18B, the fastener 280 includes a cap 282 andan anchor 284 which is configured as a tubular mesh. The tubular mesh284 has an unexpanded diameter and an expanded diameter. The post 286 ofthe cap 282 is dimensioned to fit within the lumen of the tubular mesh284 to expand the mesh to its expanded diameter. The post 286 mayinclude ridges or ring-like structures 288 disposed thereon to aid inthe expansion of the tubular mesh anchor 284. In an exemplary method ofuse, the anchor 284, in its unexpanded diameter, is positioned in tissue290. A hole 292 may be drilled into the tissue 290 for receiving theanchor 284 if desired. A bone plate or other implant 294 is placedadjacent the bone 290. The cap 282 is moved through the plate 294 andtissue 290 and into the lumen of the mesh 284.

The mesh achieves its expanded diameter in at least one of two ways.First, the insertion of the post (with ridges) into the mesh causes themesh to expand thereby preventing the anchor from pulling out of thetissue. Alternatively, the post with or without ridges may be insertedinto the lumen of the mesh while the mesh maintains its unexpandeddiameter. Ultrasonic energy and pressure from the welding horn may beapplied to the cap causing it to swell thereby locking the anchor intothe tissue. It is also contemplated that a combination of expansionmethods may be used. That is, the post with ridges may be inserted intothe lumen of the mesh causing the anchor to expand. Then, ultrasonicenergy may be applied to the fastener to further expand the mesh andbond the cap to the anchor.

Another embodiment of an expandable fastener 300 is illustrated in FIGS.19A and 19B. A top or bottom view of the anchor 302 is shown in FIG.19A. The anchor 302 includes two or more arced members or longitudinalportions of a tube 304. When placed together as in FIG. 19A, the anchor302 is in an unexpanded configuration. The cap 306 includes a post 308and lid 310. To fasten a bone plate or other implant 312 to tissue 314,the anchor 302 in its unexpanded configuration is inserted into thetissue 314. The post 308, which may include a tissue-piercing point, isinserted through the plate and tissue. As the post 308 enters the anchor302, the arced members 304 are moved outwardly or radially. This ispossible because the inner bore diameter of the anchor 302 in itsunexpanded configuration is smaller than the diameter of the post 308 ofthe cap 306. Once the cap 306 is pressed into the anchor 302, it isultrasonically welded to the anchor 302. The anchor and fastener areprevented from being pulled out of the tissue because the proximal endsof the expanded arced members of the anchor contact the tissue. The lidof the cap holds the bone plate firmly against the tissue.

The trauma welding system of the present invention also providesfasteners configured as triangulation staples. Examples of these staplesare illustrated in FIGS. 20A-20E. In FIG. 20A, the staple 320A includesfirst and second nails or braids 322A. The nails 322A include a longpost and a head disposed on the proximal end of the post. The head maybe slanted, angled, or pivotable to allow the head to seat flush againstan implant or tissue. The distal end of the post includes a tissuepiercing tip 328A. The nails 322A may include a central bore configuredfor receiving an end effector. As shown, the fastener 320A includes twonails; however, it is contemplated that the triangulation staples of thepresent invention may include three or more nails. The staple 320A ofFIG. 20A is shown holding two bone plates or other implants 330A and332A against each other at their edges. The first nail 322A is insertedthrough the first plate 330A near the edge of the first plate. The firstnail 322A is angled generally between 30 and 60 degrees with respect tovertical. A second nail 322A is inserted through the second plate 332Anear the edge of the second plate. The second nail 322A is also angledsuch that the distal tips 328A of the first and second nails contacteach other. Ultrasonic energy is applied to the nails 322A to bond thedistal tips 328A together to form a bonding area 334A. The nails 322Amay also be welded to the plates 330A and 332A where the nails passedthrough the plates. Additionally, the edges of the bone plates may beultrasonically welded together. When implanted, the staple 320A securelyholds the two plates 330A and 332A together and fastens the plates totissue, such as bone.

In FIG. 20B, the triangulation staple 320B includes two nails 322B witha suture or cable 324B connected with the heads of the nails. In anexemplary use of this staple configuration, an implant 330B ispositioned adjacent another implant or tissue 332B. The first nail 322Bof the staple is inserted into the tissue 332B on one side of theimplant 330B. The second nail 322B is inserted into the tissue 332B onanother side of the implant 330B. The cable 324B, spanning between thenails, contacts the implant 330B. As the nails 322B are driven furtherinto the tissue 332B, the cable 324B tensions and presses the implant330B against the tissue 332B. Also, with the nails firmly implanted inthe tissue, the distal tips 328B of the nails 322B contact each other.Ultrasonic energy may be used to weld the distal tips 328B together toform a bonded region.

The triangulation staple 320C of FIG. 20C is a one-piece design. Thefirst and second nails 322C are connected to each other by a crossmember 326C attached at the proximal ends of the nails. The nails 322Cmay be rotatable or pivotable from their connection with the crossmember 326C. The distal ends of the nails may include tissue-piercingtips 328C. In a pre-implantation configuration, the nails 322C extendgenerally perpendicular to the cross member 326C. In use, the staple320C is inserted through tissue, an implant, or both. The staple isinserted with the nails 322C being generally perpendicular to the crossmember. Once positioned, the nails 322C may be pivoted such that thedistal tips of the nails contact each other. The rotation of the nails322C may be performed by an instrument designed to angle the nails, forexample by using the central bore therein. With the tips in contact, thenails 322C may be ultrasonically welded together to form a securefixation of the implant and/or tissue.

In FIGS. 20D and 20E the staple 320D includes a cross member 326D whichhas channels for allowing the nails 322D to slide therein. The channelshave a central axis which intersect below the cross member 326D suchthat when the nails 322D are moved distally through the channels, thedistal tips 328D of the nails connect each other, similar to thepreviously described embodiments. As seen in FIG. 21E, the cross member326D includes one thru-channel 338D and one edge-channel 340D. Thisconfiguration allows the nails 322D to be inserted sequentially (not atthe same time, if desired). In an exemplary method of use, the firstnail 322D is partially positioned in the implant (or tissue) to befastened. The first nail 322D is angled relative to vertical at an anglegenerally equal to angles or the channels of the cross member 326D.Then, the edge-hole 340D of the cross member 326D is positioned aroundthe first nail 322D. The second nail 322D is inserted into the thru-hole338D of the cross member 326D, and both nails 322D are fully insertedinto the implant/tissue. The distal tips 328D of the nails 322D may beultrasonically welded together, and the nails 322D may be ultrasonicallywelded to the cross member 326D.

An exemplary staple welding horn 350 is shown in FIG. 21. The horn 350includes two elongate horn shafts 352 disposed in channels in a hornbase 354. The horn shafts 352 may be slideable within the channels. Boththe horn shafts 352 and the horn base 354 may emit ultrasonic energy forwelding the thermoplastic material, such as PEEK, of the above describedstaples. In use, the horn shafts 352 are retracted proximally. The horn350 is placed over the staple such that the horn shafts 352 align withthe central bore in the nails. It should be noted that the nails of thestaples previously described may include longitudinally extending boresnot only to receive the ultrasonic horn but also to receive aninstrument for positioned the nails in implant and/or tissue. With thehorn 350 properly aligned, the horn shafts 352 may be distally extendedinto the channels of the nails. Ultrasonic energy and a desired weldprofile may be used to thermally bond the staple.

Referring now to FIGS. 22A and 22B, a thermoplastic removal instrument360 is shown. The instrument 360 includes an ultrasonic welding hornshaft 362. The distal portion of the shaft 362 is generally conical andtapers inward toward the distal tip. An elongate pin 364 extends fromthe distal tip. The distal portion of the shaft 362 includes helicalthreads 366 disposed on the outer surface thereof. It is contemplatedthat besides having helical threads 366, the distal portion of the shaftmay include any engagement means such as barbs, prongs, or other similarconfigurations. To remove a thermoplastic component, the elongate pin364 of the instrument 360 is inserted into a channel of the component.The channel may already exist in the component or may need to be createdwith a drill and bit. With the pin 364 in the channel, the instrument360 is moved further distally until the distal portion of the shaft 362contacts the component. The distal portion is then threaded into thecomponent with the helical threads 366. Ultrasonic energy may then beemitted from the pin 364 to soften the thermoplastic material of thecomponent. As the material is softened, the instrument 360 may be pulledproximally, and the distal portion of the shaft 362 may begin to pullthe component out. The softened thermoplastic material adjacent the pin364 can be reshaped as the component is pulled from the implant/tissue.

In FIGS. 22A and 22B, a PEEK fastener 368 is holding a bone plate 370 tobone 372. The fastener 368 may be removed from the bone 372 with themethod just described. In FIG. 22A, with the fastener 368 in place, thedistal portion of the fastener 368 is thick thereby locking the fastener368 in the bone 372. In FIG. 22B, as the fastener 368 is pulledproximally, the distal portion thins or narrows as it is pulled from thebone 372 and plate 370. Because the fastener 368 is only softened andnot liquefied, the removal instrument 360 is able to removesubstantially all, if not entirely all, of the thermoplastic materialfrom the bone 372.

FIGS. 23A-23D illustrate a method of stabilizing a fracture bone withthe devices of the present invention. In FIG. 23A a femur 380 is shownwith a fracture 382. An intramedullary rod 384 may be placed within themedullary canal of the femur 380, as seen in FIG. 23B. The rod 384 maybe made of thermoplastic material, such as PEEK. The rod 384 ispositioned in the bone such that it spans the fracture on each side. InFIG. 23C, a plurality of channels are created in the femur 380. Thechannels are dimensioned to receive a fastener of the present invention.A first channel 386 is created in cortical bone of the femur 380. Thefirst channel 386 creates a passage from the exterior of the femur tothe IM rod 384. A second channel 388 is created in the cortical bone andslightly into the IM rod 384. The second channel 388 forms anindentation or nest in the rod 384. A third channel 390 is formedentirely through the femur 380 and IM rod 384. The third channel 390 isa thru-hole which extends through the cortex (both cortical sides) ofthe femur 380. A fourth channel 392 is created in cortical bone andpartially into the IM rod 384. The fourth channel 392 forms a blind-holein the rod 384. The channels may be formed by any means known tosurgeons, such as by a drill and bit, a guidewire, a reamer, or othersimilar instrument. It is contemplated that any number of channels andany combination of channel types may be created in the bone and IM rod.

In FIG. 23D fasteners are positioned in the channels and ultrasonicallywelded in place. Before a first fastener 394 is placed in the firstchannel 386, the surface of the IM rod 384 exposed by the channelrequires preparation for bonding. The surface may be roughened in situusing any suitable instrument. Alternatively, the surface may beroughened by the manufacture or the surgeon before implantation in thebone. With the bonding surface prepared, the first fastener 394 isplaced in the first channel 386 such that the distal end of the fastener394 contacts the bonding surface of the rod 384. An energy source, suchas ultrasonic energy, may be applied to the fastener to thermally bondthe first fastener 394 with the IM rod and femur. A second fastener 396is placed in the second channel 388 with the distal end of the secondfastener 396 positioned in the indentation in the rod 384. The secondfastener 396 may then be ultrasonically welded to the rod and femur. Athird fastener 398 is placed in the thru-hole of the third channel 390.The leading end of the third fastener 398 is configured for insertionthrough the channel, while the trailing end of the fastener may includea cap or head. The third fastener 398 is ultrasonically welded to the IMrod and femur. The leading end of the third fastener 398 may becontoured or flattened to form a leading end head. A fourth fastener 400is placed in the fourth channel 392 and within the blind hole in therod. The fourth fastener 400 is thermally welded, and the cap or head iscontoured to conform to the outer surface of the femur. It iscontemplated that the three-horn instrument of FIGS. 4A-4C may be usedto create the bonding regions, to weld the fasteners, and to contour thethermoplastic implants.

Referring now to FIGS. 24A and 24B, the devices and methods of thepresent invention are used to repair an end portion of a bone 410 havinga plurality of fractures 412. Like the repair of the fractured femur ofFIGS. 23A-23D, a PEEK intramedullary rod 414 is placed in the medullarycanal of the bone 410. A plurality of channels is created through theend portion of the bone 410 and into the IM rod 414. Any channel typepreviously described may be used in this method. A plurality ofthermoplastic fasteners 416 are placed in the channels and areultrasonically welded to the rod 414. Multiple (three or more) fasteners416 may be welded to the end portion of the IM rod 414 without reducingthe strength of the rod. Since the fasteners and rod are made of PEEK,the thermally bonded fasteners within the rod enhance the strength ofthe rod. Therefore, many fasteners may be bonded with the rod withoutlosing structural support from the channels created in the rod.

Another method and apparatus for repairing a fractured bone isillustrated in FIGS. 25A and 25B. Instead of an intramedullary rod beingplaced in the bone canal, a bone plate 420 is positioned against thefractured femur 422 on the exterior side of the bone. The bone plate 420is made of thermoplastic material such as PEEK. A first channel 424 iscreated through the plate 420 and through the bone 422 to form athru-hole. A second channel 426 is drilled through the bone plate 420,across the fracture 428, and through the bone 422. A third channel 430is formed through the plate 420 and partially into the femur 422.Additional channels may be created as desired. In FIG. 25B, PEEKfasteners 432 are placed in the channels and ultrasonically welded tothe femur 422 and bone plate 420. The fastener type and method ofwelding each fastener may be similar to previously describedembodiments.

FIGS. 26A and 26B show a combination configuration for repairing afractured bone. The combination includes an IM rod 440 positioned in themedullary canal of the bone 442 and a bone plate 444 positioned againstthe exterior surface of the bone 442. The rod and plate may be made ofPEEK. In FIG. 26A, a plurality of channels 446 are created through theplate, bone, and/or rod. PEEK fasteners, shown in FIG. 26B, arepositioned in the channels 446 and ultrasonically welded to the plate,bone, and rod. A first fastener 448 is welded to a bonding region 450 onthe surface of the rod 440. A second fastener 452 is welded in anindentation in the rod 440. A third fastener 454 extends through theplate, bone, and rod. The third fastener 454 includes a mushroomed orcontoured head on its distal end, and on the proximal end, no head isneeded since the fastener bonds directly to the bone plate 444. A fourthfastener 456 is positioned in a blind hole in the rod 440. The fourthfastener 456 is also free of a proximal head or cap. As seen in FIG.26B, the bone plate 444 is contoured to conform to the exterior surfaceof the femur 442. This may be performed with ultrasonic energy,resistive heating, or other suitable energy source.

An exemplary bone plate 460 of the present invention is shown in FIGS.27A-27C. Some previously described bone plates and IM rods included nopre-fabricated holes. Instead, the surgeon formed channels in the platesand rods to insert fasteners. In the embodiment of FIG. 27A, the boneplate 460 includes a plurality of openings. Some openings are threadedwhile others are free of treads. FIG. 27B is a cross sectional view of athreaded opening 462 of the plate 460. FIG. 27C is a cross sectionalview of an unthreaded opening 464. The plate 460 is made ofthermoplastic material such as PEEK.

Shown in FIGS. 28A-28D are exemplary fasteners for affixing the boneplate to a bone. The fasteners are made of PEEK and may include acentral channel configured for receiving a welding horn. FIG. 28A showsa PEEK fastener 470A having a threaded head 472A and a threaded shaft474A. The threaded head 472A is dimensioned to be threaded into one ofthe threaded openings 462 of the bone plate 460. The thread shaft 474Ais configured for insertion in tissue. FIG. 28B shows a fastener 470Bwith a smooth, unthreaded head 476B and a threaded shaft 474B. Theunthreaded head 476B is configured for insertion in one of theunthreaded openings 464 of the bone plate 460. FIG. 28C shows a fastener470C having a threaded head 472C and smooth shaft 478C. FIG. 28D shows afastener 470D with a smooth head 476D and smooth shaft 4780. In use, thebone plate is positioned on a fractured bone. Fasteners of FIGS. 28A-28Dare positioned through the openings in the plate and into the bone. Thefasteners are ultrasonically welded to the plate and bone. The smoothhead or smooth shaft of a fastener is thermally bonded to the plate ortissue, while the threaded head or threaded shaft is mechanicallysecured and thermally bonded to the plate and/or tissue.

The trauma welding system also provides for the modular assembly ofimplants intracorporeally. In FIG. 29, spinal cages 480 includethermoplastic material which may be welded to vertebral body replacementcomponents 482. The use of ultrasonic energy to weld the assemblytogether in the body prevents damage to surrounding tissue since thevibration energy creates just enough heat to soften and make tacky thethermoplastic material. FIG. 30 illustrates a modular IM rod 484 and amodular bone plate 486. The IM rod 484 includes a first portion 484Awelded to a second portion 484B at a bonding region 488. The secondportion 484B is welded to a third portion 484C at another bonding region488. In this embodiment, the smaller portions of the rod may beimplanted using minimally invasive techniques. Each portion may bewelded to an adjacent portion intracorporeally. The bone plate 486,likewise, includes a plurality of modular portions 486A, 486B, 486Cwhich may be thermally bonded together in the body. It is alsocontemplated that the small portions of the rod, plate, or other implantmay be assembled by the surgeon in the operating room prior toimplantation. This way, the implant manufacture can produce smallportions of an implant allowing the surgeon to select the size andnumber of portions to assembly to create a custom tailored implant. Itis contemplated that intracorporeally sequential welding applies toother types of implants as well, such as modular stents, modularacetabular component, modular spacers, and modular wedges.

In a further embodiment of the present invention shown in FIGS. 31A and31B, the trauma welding system may be used to stabilize joints of thespine such as intervertebral joints and facet joints. Stabilization ofthe spine is achieved by attaching rigid rods, plates, spacers, orwedges 490 between two or more vertebrae. Fasteners 492, such as pediclescrews, are inserted into the vertebrae, and plates/rods 490 areconnected to the screws 492. The spinal rods, plates, fasteners, etc.may include thermoplastic material, such as PEEK. The implants may bebiodegradable or biostable. In FIG. 31B, PEEK pedicle screws 492 areinserted into vertebral bodies using the methods described herein. PEEKstabilizing plates 490 span the pedicle screws 492 and areultrasonically bonded with the screws. Stabilizing cross bars 494 arethermally welded to the stabilizing plates at bonding regions 496. It iscontemplated that any combination of fasteners, rods, plates, and wedgesmay be ultrasonically welded to stabilize joints of the spine.

In FIG. 32 a spacing fastener 500 is shown. The fastener 500 includes ananchor 502 and a cap 504. The anchor 502 is generally a cylindricalshaft with a head 506 disposed on the proximal end of the shaft 508. Theshaft 508 may include helical threads 510 for mechanical locking intotissue 512. The anchor 502 includes a bore extending along the centralaxis of the anchor. The fastener 500 further includes a cap 504 having apost 514 and a lid 516 attached to the proximal end of the post. Thepost 514 is dimensioned and configured for insertion into the bore ofthe anchor 502. Both the cap and anchor may be made of thermoplasticmaterial such as PEEK. In an exemplary method of use, the anchor 502 isimplanted in tissue 512 as shown in FIG. 32. The anchor 502 may bemechanically and/or thermally bonded in the tissue. A bone plate or rod518 is placed over the head 506 of the anchor 502. A pre-drilledpassageway 520 formed in the plate by the manufacturer is aligned withthe bore of the anchor. Alternatively, a passageway 520 may be formed bythe surgeon and aligned with the bore. The cap 504 is inserted throughthe passageway 520 of the plate 518 and into the bore of the anchor 502.The cap, plate, and anchor may be thermally bonded together withultrasonic energy. In the implanted configuration, the head 506 of theanchor 502 acts as a spacer between the tissue 512 and plate 518. Thespacing fastener 500 of FIG. 32 may be used as a pedicle screwseparating a stabilizing plate from vertebral bodies.

In a further embodiment, the trauma welding system may be utilized toprovide flexible stabilization of the spine, or any other joint or boneof the body. The soft tissue around and near a joint may become weakenedover time, and the range of motion of the joint usually increasesthereby allowing excessive tissue laxity. Also, instability of a jointmay be caused by structural changes within the joint as a result oftrauma, degeneration, aging, disease, or surgery. An unstable spinaljoint may be rigidly stabilized as previously explained or may bedynamically stabilized to allow some range of motion of the spinaljoints. Fasteners, screws, plates, rods, etc. made of PEEK may beimplanted between two or more vertebrae. The plates and rods areconfigured and dimensioned to permit some flexing and/or bending. Theamount of flexibility of these PEEK implants may be adjusted by thesurgeon in the operating room using energy, such as ultrasound,resistive heating, etc. and by varying the weld parameters.

As seen in FIG. 33, a plate or rod 530 may be configured to lock with afastener 532 in one direction, but would allow movement in anotherdirection. For example, the plate 530 and fastener 532 permits superiorand inferior motion of the spine but would prevent lateral motion. Also,the plate 530 and fastener 532 may permit motion in one plane andrestrict motion in a different plane. The fasteners and plates of FIG.33 may be made of PEEK and may be ultrasonically bonded to stabilize thespine.

FIGS. 34A and 34B illustrate another embodiment to stabilize a jointsuch as a joint of the spine. The swivellable pedicle screw assembly 540may be used to connect a longitudinal bar 542 to a pedicle screw 544thereby forming a spine stabilization device. The assembly 540 includesa body 546 having an upper end, a lower end, a hole 548 which is open atleast towards the bottom and has an axis, and a through hole positionedperpendicular to the axis. The assembly 540 also has a collet chuck 550mounted coaxially on the inside of the body 546 in such a way that itcan slide along the axis. The collet chuck 550 has a through hole 552which is flush with the through hole of the body 546, and a chamberwhich faces at least downwards and is defined by tongues spring mountedagainst the cylinder axis. When the collet chuck 550 is inserted in thebody, the through holes 552 align to allow insertion of the longitudinalbar 542. The head 554 of a pedicle screw 544 can be clicked into thechamber from below by spring-action. The assembly 540 allows for thepedicle screw 544 to be inclined within a certain range. The assemblymay be made of thermoplastic material such as PEEK. Ultrasonic energymay be used to thermally bond the head 554 of the pedicle screw 544within the chamber of the collet chuck 550 and to bond the longitudinalbar 542 with the pedicle screw 544.

It is contemplated that a simple ball and socket assembly may be used tostabilize the spine as well. The ball is the head of the pedicle screwas described above. The socket includes a chamber for receiving theball. The socket may include an attachment means, such as a thru-hole ora thermal bonding region, for receiving and affixing a plate or rod. Theball, socket and plate/rod may be ultrasonically welded together to forma spin stabilizing configuration.

FIGS. 35A and 35B illustrate a bone fixation assembly 560 for securing abone plate to bone. The assembly 560 includes the fixation device 562, abushing 564, a fastening screw 566, and a locking screw 568. The bushing564 is seated within a through hole in the fixation device 562 and canrotate within the through hole and has a sidewall with a bore. Thesidewall has at least one slot for allowing outward expansion of thesidewall against the through hole to thereby lock the bushing 564 at aselected angle relative to the axis of the through hole. The fasteningscrew 566 has a threaded shaft 570 for insertion through the bore of thebushing 564 and threads into bone to secure the bushing 564 and fixationdevice 562 to bone. The head of the fastening screw 566 fits in thebushing and includes a radial wall and open end defining a recess. Theradial side wall has at least one slit for allowing outward expansion ofthe radial wall thereby outwardly expanding the sidewall of the bushing564. The locking screw 568 has a body that threads in the head of thefastening screw 566 to thereby outwardly expand the radial wall of thefastening screw 566. The assembly components may be made of PEEK. In analternative embodiment, a fastening member 572, made of PEEK, replacesthe fastening screw 566 and locking screw 568. In this embodiment, thefastening member 572 is inserted through the bore of the bushing 564 andinto the bone. The fastening member 572 may be ultrasonically welded tothe bushing 564 and the bushing, 564 may be thermally bonded to thefixation device 562. The fastening member 572 is ultrasonically bondedto the bone using the welding methods described herein.

Referring now to FIGS. 36A and 36B, a cable tensioning fastener 580 isillustrated. The fastener 580 includes a post 582 and a cap 584 disposedon the proximal end of the post. The post 582 is configured for windinga suture or cable 586 thereon. The suture 586 may be attached to thepost 582 by applying heat to PEEK material of the post, setting thesuture into the softened PEEK, and allowing the PEEK to harden.Alternatively, a small channel may extend radially through the post. Thesuture 586 may be threaded through the channel. In a simpleconfiguration, the suture 586 may be wrapped over itself on the post582, like a spool of string. In an exemplary method of use as shown inFIGS. 36A and 36B, the suture or cable 586 is placed through or aroundtissue 588 such as a rotator cuff. The suture 586 is attached to thepost 582 of the fastener 580 as previously described. The fastener 580is then rotated to coil up the suture 586 on the post 582 and draw therotator cuff 588 in close to the fastener 580. To secure the assembly,the fastener 580 is inserted into tissue such as bone 590. Ultrasonicenergy is applied to the fastener 580 to bond the fastener to the tissue590 and bond the suture 586 to the post 582 of the fastener 580. In thisposition, the rotator cuff is securely fastened to the bone.

FIG. 37 illustrates another exemplary use of the cable tensioningfastener 580 of FIGS. 36A and 36B. A first tensioning fastener 580 ispositioned in a vertebral body 592. A second fastener 580 is positionedin an adjacent vertebral body 592. A cable 586 spans between the postsof the first and second fasteners. One or both fasteners are rotated totension the cable, and the fasteners are implanted in the vertebrae andultrasonically welded in place. Third and fourth fasteners are implantedin spinous processes 594. A tensioned cable 586 is connected with thefasteners 580. The embodiment of FIG. 37 provides controlledstabilization of the spine by affixing flexible or non-flexible cablesbetween vertebrae. Flexible cables provide dynamic stabilization, whilenon-flexible cables provide rigid stabilization.

The present invention also provides a glenoid replacement component600A, shown in FIG. 38A. The inner side is configured for placement onthe scapula 602, and the outer side is configured for articulation ofthe head 604 of the humerus 606. Thermoplastic fasteners 608 secure thecomponent 600 to bone. In FIG. 38B, a glenoid replacement component 600Bis shown having prongs 610 extending from the inner side. The prongs 610may be inserted into pre-drilled holes in the scapula and ultrasonicallywelded therein. FIG. 38C illustrates another embodiment of a glenoidreplacement component 600C. The component 600C includes two thru-holes612 extending from the outer to the inner side of the component. PEEKfasteners may be used to secure the replacement component to bone. Thecaps or heads of the fasteners may be contoured and flattened so as tonot interfere with the head of the humerus.

Referring now to FIG. 39, a thermoplastic cross pin 620 is illustrated.The pin 620 may be made of PEEK. The cross pin 620 is used to stabilizeand strengthen the neck 622 and head 624 of the femur 626. To implantthe pin, the pin 620 is positioned in a channel extending into the neck622 and head 624. The pin 620 may be mechanically locked within thechannel and/or may be thermally bonded within the channel. Thermoplasticfasteners 628 are placed through the cortical bone of the femur 626 andinto contact with a bonding region on the pin 620. As previouslydescribed, the bonding region may be a roughened surface, anindentation, a blind-hole, or a thru-hole. The fasteners 628 are thenultrasonically welded to the pin 620 and bone to secure the pin 620within the femur 626. FIG. 40 illustrates a cross pin jig 630 to be usedduring implantation of the pin 620. The jig 630 includes a shaft 632 anda series of pivoting arms 634 connected with the shaft 632. At the endof the pivoting arms 634 is an insertion guide 636. The guide 636 has apassageway 638 configured for guiding a fastener. The arms 634 pivot inone plane with respect to the shaft 632 such that the passageway 638 ofthe insertion guide 636 is always aligned with the shaft 632. In use,the shaft 632 of the jig 630 is inserted into the drilled channelextending into the neck and head of the femur. The insertion guides 636are positioned adjacent the surface of the bone. A drill and bit isplaced in the guide 636 and a hole is created through the cortical boneterminating in the channel. A plurality of holes may be formed in thebone to receive a plurality of fasteners. Once the holes have beendrilled, the jig 630 is removed and the cross pin 620 is inserted intothe channel. Fasteners are then placed through the holes and intocontact with the cross pin 620. Ultrasonic welding bonds the fasteners,cross pin, and bone together. In an alternative embodiment, the shaft ofthe jig has a diameter which slides into a central passageway of thecross pin. In this embodiment, the cross pin may be implant in thechannel, then the jig may be placed in the cross pin.

In a related invention, FIG. 41 shows a tissue cauterization device 640.A cut or opening 642 is formed in soft tissue such as skin 644. To stopbleeding at the cut, ultrasonic energy may be applied to the tissue. Anenergy horn 640, similar to those previously described, may be placed incontact with bleeding tissue 644. Ultrasound energy emitted from thehorn stops the flow of blood by hemostasis. In FIG. 42, ultrasound froman energy horn 640 is applied to gelatin 648 within a joint 650. Thegelatin 648 binds to the tissue and stops bleeding. Gelatin, or othersuitable substance, may also be used with the tissue cauterizationdevice of FIG. 41.

FIG. 43 illustrates a periosteal flap 660 used to repair a damaged bone662. The flap 660 is fastened to the bone 662 using thermoplasticfasteners 664 and methods previously described. Tissue grafts may alsosecured intracorporeally using PEEK fasteners and ultrasonic energy.

It is also contemplated that metal may be ultrasonically welded to PEEK.For example, a fastener may be made of metal. By placing the metallicfastener on the end effector of the welding instrument, the fastenerfunctions as an extension of the end effector. Therefore, applyingpressure from an ultrasound-emitting metallic fastener to a PEEK implantdrives the fastener into the implant and thereby secures the fastener tothe implant. It is further contemplated that a thermoplastic fastenermay be bonded with a metallic implant. Accordingly, the devices andmethods described throughout may utilize metallic fasteners bonded tothermoplastic implants and thermoplastic fasteners bonded to metallicimplants.

In a further embodiment of the present invention, a method for securinga thermoplastic fastener 670 into tissue 672 is provided. FIGS. 44A and44B illustrate the method. In FIG. 44A, a channel 674 in drilled intissue such as bone 672. The fastener 670 includes a post 676 and a lid678, similar to other fasteners disclosed herein. The diameter of thepost 676 is greater than the diameter of the channel 674 in the bone 672such that the fastener 670 does not freely slide into the channel 674.In FIG. 44B, an end effector 680 is placed in and on the fastener 670.Ultrasonic energy is emitted from the end effector 680 to soften thethermoplastic material of the fastener 670. Simultaneously, downwardpressure is applied to the end effector 680 and fastener 670 so that thesoftened material conforms to the smaller diameter of the channel 674.The fastener 670 is moved distally until it is fully seated in the bone672. After energy is no longer emitted, the thermoplastic materialre-hardens thereby securely bonding the fastener 670 to the bone 672.

In another application of the present invention, thermoplastic fastenersmay be used to lock a drug delivery system to an implant or to tissue.For example, a reservoir, balloon, or bladder may be placed within thebody and filled with a pharmaceutical substance, gene therapy, or celltherapy. Using PEEK or other thermoplastic, the reservoir may be sealedand stabilized in the body. The contents of the reservoir may leach outor elute out from pores or openings in the reservoir material.Alternatively, the thermoplastic may be biodegradable to allow thecontents to escape from the reservoir and into the body. It iscontemplated that other drug delivery systems may be used with thepresent invention. Also, the pharmaceutical agents may includeantibiotics, hydroxyapatite, anti-inflammatory agents, steroids,antibiotics, analgesic agents, chemotherapeutic agents, bonemorphogenetic protein (BMP), demineralized bone matrix, collagen, growthfactors, autogenetic bone marrow, progenitor cells, calcium sulfate,immo suppressants, fibrin, osteoinductive materials, apatitecompositions, germicides, fetal cells, stem cells, enzymes, proteins,hormones, cell therapy substances, gene therapy substances, bone growthinducing material, osteoinductive materials, apatite compositions withcollagen, demineralized bone powder, or any agent previously listed.U.S. Provisional Patent Application No. 60/728,206 entitled “DrugEluting Implant” discloses means for delivering therapeutic agents. Theabove-mentioned provisional application is incorporated by referenceherein in its entirety.

The welding system of the present invention may further include theprocess of welding collagen similar to the way PEEK is bonded. Collagenfibers may be infused within a biodegradable polymer or gelatin toenhance welding properties. An energy source, such as ultrasonic energy,may be used to weld the collagen. As previously described the quality ofweld depends upon the welding parameters of time, energy time, wattage,frequency, pulsation, pressure, etc. In an exemplary embodiment,collagen is placed in biodegradable polyglycolic acid. Once implanted,the polymer would biodegrade leaving the collagen fibers to healsurrounding tissue. Also, imbedded in the polymer may be cells,antibiotics, keratin, tissue inductive factors, or other pharmaceuticalagents disclosed herein.

Alternatively, the collagen fibers may be packed very densely and may bedesiccated. The fibers may be welded together or an interfacial materialsuch as talc, glass, graphite, or protein may be added to harden thefibers to a gelatin. In an exemplary embodiment, collagen fibers may becombined with denatured porcine collagen cells. The two substances maybe welded together to form a unitary implant. The implant may befastened within the body for cell therapy, gene therapy, or for thedelivery of pharmaceutical agents.

Another welding technique that may be utilized with the presentinvention is plasma welding. Generally, there are four states of matterin physics: solid, liquid, gas, and plasma. Plasma is a gas in whichatoms have been ionized. Therefore, plasma has magnetic and electricalfields that move unpredictably, altering the environment. As theenvironment changes, so does the plasma. These ionized gasses or plasmacan be used to fuse, bone or weld material within the body. Plasmawelding may be controlled similar to the way thermal welding iscontrolled as previously described. A plasma stream may be used forpolymeric welding, protein welding, or collagen welding. When weldingintracorporeally, cold plasma welding may be used to prevent tissuenecrosis. Cold plasma can weld tissue, polymers, metals, ceramics, andcomposites to each other and to one another. Cold plasma may also beused to debride wounds in surgery, to selectively kill bacteria, toroughen the surface of tissue to make it more receptive topharmaceutical agents, or to prepare a surface of a bone for a jointreplacement component. It can also be used to shrink tissue andpolymers, ablate tissue, or smooth out wrinkles for plastic surgeryeither on the surface of the skin or under the skin. Cold plasma weldingmay be performed through a cannula in a straight line orcurved/deflected to reach a target site within the body. The plasmaenergy may be altered by accelerating electrical charges orelectromagnetic fields.

In a related invention, welding of thermoplastics, tissue, implants,etc. described herein may be performed utilizing suction or negativepressure. For example, suction may be applied to a bone to pull acartilage graft or plate to the surface of the bone. A tube may beplaced within the bone to create a negative pressure. This wouldtemporarily hold the implant and contour it to the surface while anenergy source is used to weld the graft to the bone with or withouttraditional or thermoplastic fasteners. Also, suction may be used tostabilize an implant during welding or while an adhesive is curing.Examples of biocompatible adhesives include mollusk adhesive, proteinadhesive, fibrin adhesive, cyanoacrylates, or other known adhesives.

The present invention also may be used in other ways for the fixation orsecuring of tissue and/or implants during a surgical procedure. The useof the invention in such a procedure may assist in restoring at leastpartial tissue-function in a treated area. In this scenario, thefixation device may include a tissue-penetrating cap positionable in ananchor. Tissue may be fastened so that tissue-function is at leastpartially restored and the operation region is stabilized for enhancedhealing.

The fixation devices of at this and other embodiments of the inventionmay be used in combination with fasteners in the prior art. Examples offasteners, implants, and their methods of employment may be found inU.S. Pat. Nos. 5,163,960; 5,403,348; 5,441,538; 5,464,426; 5,549,630;5,593,425; 5,713,921; 5,718,717; 5,782,862; 5,814,072; 5,814,073;5,845,645; 5,921,986; 5,948,002; 6,010,525; 6,045,551; 6,086,593;6,099,531; 6,159,234; 6,368,343; 6,447,516; 6,475,230; 6,592,609;6,635,073; and 6,719,765. Other fastener types are disclosed in U.S.patent application Ser. Nos. 10/102,413; 10/228,855; 10/779,978;10/780,444; and 10/797,685. The above cited patents and patentapplications are hereby incorporated by reference in their entirety.

FIG. 45 illustrates an exemplary embodiment of a fixation device 682 ofthe present invention, where the fixation device includes a cap 684 andan anchor 686. The anchor 686 is generally cylindrical in shape andincludes a bore 688 disposed in a first end of the anchor 686. A secondend of the anchor may be substantially conical, although as explained ingreater detail below the second end may have other shapes as well. Thecentral longitudinal axis of the bore 688 may be congruent with acentral longitudinal axis of the anchor 686. The bore 688 may extendonly partially into or completely through the anchor 686. The anchor ofFIG. 45 includes threads 690 in a helical pattern disposed on theexterior surface. The helical threads 690 are configured to allow theanchor 686 to be inserted in tissue similar to the way a screw isinserted into wood, with or without a pre-drilled hole.

The cap 684 of the fixation device 682 includes a lid 692 and a post694. The post 694 is generally cylindrical in shape and is dimensionedto fit within the bore 688 of the anchor 686, while the lid 692 isgenerally disk shaped. The proximal end of the post 694 is connectedwith the underside of lid 692 to form a fastener configuration similarto a nail. The cap 684 may be cannulated, i.e. a channel may extendthrough the longitudinal axis of the cap. The channel may be dimensionedfor the positioning of a guide wire, insertion tool, and/or energysource therein. The distal portion of the post 694 may be chamfered toform a pointed tip 696. The chamfered surfaces of the distal portion mayextend from the distal opening of the channel to the outer surface ofthe post 694. The chamfered post tip 696 allows the cap 684 to penetratethrough tissue without substantial tearing.

The post 694 of the cap 684 and bore 688 of the anchor 686 may furtherinclude one or more mechanical locks that may be used to help hold thecap 684 and anchor 686 together when desired. For example, a mechanicallock can be used to hold the cap tip 696, post 694, or other portions ofthe cap 684 within the anchor 686 when the device is being employed tosecure tissue and/or an implant. Examples of mechanical locks mayinclude one or more projection 698 disposed on the outer surface of thepost 694. FIG. 45 illustrates one example of a projection where the cappost 694 has a circumferential ridge 698. One or more correspondingindentation(s) or grooves may likewise be provided in the surface of theanchor bore. Alternatively, one or more projections may be provided onthe anchor bore, and the cap post may have one or more indentations orgrooves.

Other mechanical locks may also be used with this and other embodimentsof the invention. For example, a mechanical lock may utilize amechanically, outwardly expanding post and/or a mechanically, inwardlyexpanding anchor/bore; a hydrophilically, outwardly expanding postand/or a hydrophilically, inwardly expanding anchor/bore; helicalthreads on the post and corresponding threads in the bore; andbiocompatible adhesive disposed in the bore of the anchor and/or on thepost of the cap. Examples of adhesives may include cyanoacrylateadhesives, hydrogel adhesives, monomer and polymer adhesives, fibrin,polysaccharide, Indermil® or any other similar adhesive. Other exemplarymechanical locks discussed in greater detail herein may also be appliedto many embodiments of the invention.

Alternatively, the cap 684 may be secured to the anchor 686 by thermalfastening. As previously explained, certain materials of the cap 684 andanchor 686 may have the characteristic of becoming melted, tacky, and/orflowable when energy such as heat is applied to the fixation device. Thematerial may be resorbable by the body or non-resorbable. Such materialmay include polylactic acid (PLLA), polyglycolic acid (PGA), aco-polymer of PILA and PGA, resins, polyetheretherketone (PEEK),polyethylene (PE), ultra-high-molecular-weight-polycarbonate (PC),acetal (Delrin), and other suitable polymers. The thermally bondingmaterial may be dispersed within the cap and anchor and/or may be coatedon the surface of the cap and anchor. Additionally, the cap and theanchor may be made entirely from the thermally bonding material.

In an exemplary embodiment, the fixation device is made of PEEK which isa suitable thermally bondable material. Also, an implant in which thefixation device fastens to tissue may include a thermally bondablematerial. For example, a plate, rod, spacer, wedge, or other implantsdisclosed herein may be secured to tissue. An energy source, such asultrasound or resistive heating, may be used to secure the cap to theanchor and to secure the implant to the fixation device. The energysource also may heat the implant which may include thermally deformablematerial, such as PEEK. The implant may also be deformable orconformable to adjacent tissue.

To bond the cap 684 and anchor 686 of the fixation device 682 together,an energy source may be applied to one of or both of the cap 684 andanchor 686. Suitable energy sources may include ultrasonic; RF; laser;heat transmitted through conduction, convection, or radiation; resistiveheating; microwave; electromagnet; ultraviolet; infrared;electro-shockwave; or other known energy sources. The cap 684 and anchor686 may also be coupled by protein welding. Preferably, when the cap 684and anchor 686 are designed to be thermally coupled, at least a portionof both the cap and anchor include, or are made of, a thermally bondablepolymer, such as those previously described. The use of energy to bondthe cap 684 and anchor 686 which have similar polymeric material allowsthe melting of the material to occur consistently or uniformlythroughout welded area of the fixation device 682. This helps reduce therisk of necrosis to the surrounding tissue and also is believed toprovide better control of welding conditions. If the, thermally bondablematerial is metal, magnetic pulse welding could be used to bond the capand anchor of the fixation device.

To apply an energy source to the fixation device 682, the energyproducing instrument may include a projection, such as an arm, which ispositionable within the cannulated cap 684 and anchor bore 688. In thisconfiguration, energy may be emitted from the projection and into thecap 684 and anchor 686. Since the projection extends through thecannulated cap and anchor, the fixation device 682 is subjected toenergy along its longitudinal length. Therefore, the material of the cap684 and anchor 686 may be bonded in a consistent, even, and/or uniformmanner.

It is also contemplated that the fixation device 682 may include energyfocusing material. The energy focusing material may be particles orchips disposed within the material of the cap 684 and/or anchor 686. Theenergy focusing material also may be a sleeve or particles disposed inthe channels of the cannulated cap 684 and anchor bore 688. The energyfocusing material may also be dispersed in rings or discs disposedwithin the material of the device 682. The rings may be positionedgenerally perpendicular to the longitudinal axis of the device.Furthermore, the energy focusing material may be disposed in bars orrods positioned generally parallel to the long axis of the device. Theenergy focusing material may be metallic, ceramic, polymeric, composite,or other suitable material. For example, iron oxide may be used. Theenergy focusing material may help capture energy from an energy sourceand/or emit energy for bonding the cap and anchor to each other.

An exemplary process for ultrasonic welding is illustrated in FIG. 46.The welding process begins by either pushing the generator footswitch orusing the control on the hand piece. Upon starting, the generator mayfirst perform a system check. The software may also check for properpatient grounding, ground offset issues, as well as other vitalcircuits. If there are errors with the system or the grounding, thegenerator can give a visual or audible indication that an error hasoccurred, and the ultrasonic signal generator may be disabled to preventinadvertent use.

If no errors are detected, the system may then sweep a frequency range,such as from about 38.5 kHz to about 43.5 kHz, to tune the circuit.Current measurements may be used to find the resonate frequency of thesystem, which in some embodiments may be close to 41 kHz. The ultrasonicsignal is then sent to the hand piece where a resonator turns thewaveform into linear movement.

Welding of the fixation device of the present invention could also bedone using thermal energy. The process for thermal welding is similar tothe one used for ultrasonic, except that it may not be necessary to tunethe system. The energy signal sent to the weld can be either AC or DC.To allow for longer heater life, a pulse width modulated (PWM) signalcould be used. The PWM signal allows for the energy to be rapidlyswitched on and off with a varying duty cycle proportional to the totalsystem energy needed for the weld environment.

Another way to connect the cap and anchor of the fixation device may bethrough the combination of mechanical locking and welding. For example,the outer surface of the cap post 694 may include a circumferentialridge 698 and the interior surface of the anchor bore 688 may include acorresponding circumferential groove. Both the cap 684 and anchor 686could include, or be made of, a biocompatible, thermally bondingpolymer. The mechanical lock of the fastener could hold the cap 684 inthe anchor 686 while an energy source, like an ultrasonic welder, isused to melt and bond the cap 684 and anchor 686 together. In thisconfiguration, the mechanical lock may act as a temporary hold until thecap 684 and anchor 686 are permanently welded together. Thisconfiguration allows a surgeon to temporarily connect the cap 684 andanchor 686 and then inspect the assembly and tissue or implant toconfirm it is in a desired position.

Alternatively, the fixation device 682 may include a more permanentmechanical lock in combination with thermal bonding. For example, thecap post 694 may include helical threads and the anchor bore 688 mayinclude corresponding helical threads 690. In this configuration the cappost 694 may be screwed into the anchor 686 to securely connect the capand anchor. The holding power of the cap and anchor may then be enhancedby thermally bonding the material of the cap and anchor together.

As previously described, the anchor 686 of the fixation device 682 maybe screwed into a pre-drilled passageway in bone. The helical threads690 disposed on the outer wall of the anchor allow the anchor to bescrewed into and secured in the drilled passageway. Another way toimplant the anchor 686 is by providing a self-penetrating orself-tapping helical thread configuration. In this configuration, theleading tip of the anchor 686 includes sharp edges, similar to thedistal end of a drill bit, to allow the anchor to penetrate hard tissueas the anchor is being rotated. Such an anchor may include rigid threadsand/or a rigid exterior wall on which the threads are disposed. Therigid exterior surface may include metal or ceramic material whichfunctions as a shell. Within the rigid shell may be a polymer inner coreincluding thermally bondable material. The benefits of this anchordesign are that it is self-tapping requiring no pre-drilled passagewayin bone and that the cap post and anchor may still be thermally bondedtogether.

Furthermore, the fixation device of the present invention may includetherapeutic substances to promote healing. These substances couldinclude antibiotics, hydroxyapatite, anti-inflammatory agents, steroids,antibiotics, analgesic agents, chemotherapeutic agents, bonemorphogenetic protein (BMP), demineralized bone matrix, collagen, growthfactors, autogenetic bone marrow, progenitor cells, calcium sulfate,immo suppressants, fibrin, osteoinductive materials, apatitecompositions, germicides, fetal cells, stem cells, enzymes, proteins,hormones, cell therapy substances, gene therapy substances, andcombinations thereof. These therapeutic substances may be combined withthe materials used to make the device. Alternatively, the therapeuticsubstances may be impregnated or coated on the device. Time-releasedtherapeutic substances and drugs may also be incorporated into or coatedon the surface of the device. The therapeutic substances may also beplaced in a bioabsorbable, degradable, or biodegradable polymer layer orlayers.

The therapeutic agents may also be placed within one or more cavitiesdisposed in a fixation device of the present invention. Different agentsmay be disposed in different cavities of the device to specificallytailor the implant for a particular patient. Dosages of the therapeuticagent may be the same or different within each of cavities as well. Thecavities may include a cover which may release the agent in a controlledor timed manner. The cover may be biodegradable or bioerodible to allowthe agent to release to surrounding tissue. Examples of suitabletherapeutic agents include bone growth inducing material, bonemorphogenic proteins, osteoinductive materials, apatite compositionswith collagen, demineralized bone powder, or any agent previouslylisted. U.S. Provisional Patent Application No. 60/728,206 entitled“Drug Eluting Implant” discloses means for delivering therapeuticagents. The above-mentioned provisional application is incorporated byreference herein in its entirety.

FIG. 47A shows a cap 700 inserted, within an anchor 702. The post 704 ofthe cap 700 is positioned in the bore of the anchor 702. A gap 706 isshown between the bottom of the cap lid 708 and the trailing end orproximal end of the anchor. When the fixation device is in use, thetissue and/or implant to be fastened may be placed in the gap 706 tothereby squeeze the tissue between the lid 708 and anchor 702.

In FIG. 47B, the interior configurations of the cap 700, anchor 702, andheater 710 are illustrated. The anchor 702 includes a bore 712 andchannel 714. The bore 712 is dimensioned to receive the post 704 of thecap 700. The channel 714 may be dimensioned to receive the distalportion of the heater 710. The channel 704 may also be dimensioned toreceive a guide wire to assist in more precise placement of the anchor702 in tissue and placement of the cap 700 within the bore 712 of theanchor 702. The cap 700 also may have a bore 716 and a channel. The capbore 716 may be dimensioned to receive an intermediate portion of theheater 710, while the cap channel may be dimensioned to receive thedistal portion of the heater 710 and/or a guide wire.

To lock the cap 700 and anchor 702 of FIG. 47B together, the cap post704 is inserted into the anchor bore and a lock 718 is actuated totemporarily resist inadvertent separation of the cap 700 from the anchor702. Preferably, the lock 718 prevents the cap 700 and anchor 702 frommoving relative to each other. The heater 710 may be inserted throughthe cap bore 716, cap channel, anchor bore 712, and anchor channel 714.The heater 710 may include a curved or angled edge 720 a part of atransition between the intermediate portion and distal portion of theheater 710. The heater 710 may be inserted until the edge 720 contactsthe cap bore 716. The portion of the cap bore 716 that contacts edge 720may be curved, angled, or otherwise configured to have a surface thatcorresponds to the contact area of the edge 720. The cap angled edge mayform the transition between the cap bore and cap channel. The contactbetween the cap and heater allows for the transmission of forces fromthe heater to the cap and to the anchor. The applied force helps createa snug fit between the cap post and anchor bore while the heater appliesenergy to the fixation device for thermal bonding.

FIG. 48 illustrates another embodiment of a fixation device 722. In thisembodiment, the cap 724 includes a channel but does not include a bore.The anchor 726 includes both a bore 728 and a channel 730. As shown, theheater 732 has a cap-contacting surface 734 between its proximal portionand distal portion. In FIG. 47B, the force was applied from the heater710 to the cap 700 through the angled edges of the heater and cap bore.However, in the embodiment illustrated in FIG. 48 forces applied to theheater 732 may be transferred to the top surface of the cap 724. Whilethe force is applied, energy from the heater 732 may be released tothermally bond the cap 724 and anchor 726. The cap 724 and anchor 726may also include one or more temporary or permanent locks 736 aspreviously described.

Referring now to FIG. 49, another embodiment of a fixation device of thepresent invention is employed to secure a first tissue type or implant740, such as a rotator cuff, to a second tissue type, such as bone 742.Alternatively, a plate 740, such as a bone plate, may be fastened to afractured bone. Although a plate 740 is shown and described, otherimplants, such as a mesh, can be used. The anchor 744 is inserted into adrilled passageway in bone 742. In this embodiment, the anchor 744includes external helical threads 746; therefore, the anchor 744 may bescrewed into the bone passageway. It is contemplated that such an anchor744 having helical threads 746 would also be configured to permitscrewing of the anchor 744 into the drilled passageway. For example, agroove may be disposed on the bottom of the anchor bore. The groove maybe configured to receive a tool, such as a fiat-head type screw driver,for rotating the anchor into the bone; the bore itself may be configuredto receive an Allen-type wrench; or the trailing end of the anchor mayinclude a groove(s) to receive a flat-head or Phillips-head type tool.In one alternative embodiment, there may be no structural feature of theanchor itself for insertion, but rather a tool may be inserted andmechanically expanded within the anchor bore to permit rotation of theanchor into tissue.

Insertion of the anchor 744 into the bone 742 may be further performedwith a guide wire 748 or other similar surgical instrument. The wire 748may be placed in the bone at the desired location for the fixationdevice. The passageway in the bone may be formed by moving a cannulateddrill bit along the guide wire 748. Then, the anchor 744 may beslideably disposed over the guide wire 748 in the anchor channel andinserted into the drilled passageway. The cap 750 is also slideablydisposed over the guide wire 748 and is moved through the soft tissue,such as the rotator cuff, and into the anchor 744. The distal tip of thecap post 752 may be chamfered to permit the post to penetrate throughthe soft tissue without significantly damaging the tissue. The cap post752 may be further aided during insertion through the soft tissue by theuse of the distal tip of the guide wire 748 or the distal tip of anenergy source, such as the one described in FIG. 48. The post 752 shownin FIG. 49 may include a chamfered leading tip having no blunt surface.A blunt-free tip and the use of a pointed guide wire or pointed energysource may allow the cap to more easily penetrate the soft tissue instages. That is, first the guide wire 748 or energy source may be usedto create a small hole in the soft tissue. Then, the blunt-free,chamfered tip of the post 752 may stretch or widen the hole to a largerdiameter without significant tearing of or damage to the soft tissue.

With the cap 750 disposed in the soft tissue, the cap post 752 isinserted into the anchor bore. A mechanical lock 754 may be utilized tohold the cap 750 and anchor 744 together while an energy source is usedto weld the cap and anchor together. In this final configuration, thesoft tissue is sandwiched between, and preferably is held firmlyagainst, the bone by the underside of the cap lid 756.

FIG. 50 shows another exemplary embodiment of a fixation device. Theanchor 760 is similar in construction to the anchor of FIG. 49. However,the anchor bore 762 and the cap post 764 do not have a mechanical lock.Instead, fastening of the cap and anchor is provided by thermal bondingonly. Preferably, both the cap 766 and anchor 760 include, or are madeof, the same or similar biocompatible polymer so that the two componentsof the fixation device may be easily welded together. With the cap post764 being free of any mechanical lock, the cap 766 is able to bepositioned anywhere within the bore 762 of the anchor 760. Therefore, ifthe tissue or implant to be fastened to the bone is thin, the cap 766may be inserted fairly deeply into the anchor 760 and welded. If thetissue or implant is thick, the same length cap may still be used withthe anchor; however, the cap post 764 is just not inserted as far intothe anchor bore 762 prior to welding. Alternatively, a plurality of capshaving differing length cap posts may also be provided so that thesurgeon may select a cap of desired length according to the type oftissue or implant used in the treated area. If two or more caps ofdiffering lengths are provided, the different sizes may be indicated onthe caps, such as by molding a size or other indicator onto the cap lid768.

One notable feature of the embodiment of FIG. 50 and other embodimentsdescribed herein is the lack of energy directors required for weldingthe cap to the anchor. Some prior art fasteners designed for thermalwelding require projections disposed between the two parts of thefasteners. Often, these directors take the form of longitudinal ridgesdisposed on the outer surface of a male fastener section or disposed onthe inner surface of a female fastener section. The purpose of thedirectors is to concentrate the energy thereon to weld the fastenersections together. As seen in FIG. 50, no directors are disposed betweenthe cap and anchor. When an energy source, such as an ultrasonic welder,is placed in the cap 766, substantially all, and preferably the entireexterior surface of the cap that is in contact with the anchor bore maybe welded to the anchor. This produces a uniform bond between the capand anchor. Alternatively, because the cap is cannulated, the distal tipof the energy source may be positioned adjacent the contact location ofthe distal end of the cap post and the distal end of the anchor bore.This allows the energy source to weld the cap and anchor at that contactlocation.

As previously mentioned, the cap and anchor of the fixation device maybe held together by a mechanical lock, by thermal bonding, or by acombination of mechanical locking and thermal bonding. The embodiment ofFIG. 51 includes an example of a fixation device 770 having a permanenttype of mechanical lock. With a permanent type of mechanical locking,thermal welding may not be necessary to hold the cap and anchor togetherbecause the mechanical lock may provide sufficient holding strength onits own. The anchor 772, as shown, is similar to the anchors previouslydescribed. However, in this embodiment, the anchor bore 774 includeshelical threads 776 disposed in the wall of the bore 774. The borethreads 776 are configured to receive threads 778 disposed on theexterior surface of the cap post. The cap 780 is insertable within theanchor by screwing the cap post 778 into the anchor bore 774. Inaddition, to enhance the holding power of the fixation device, the cap780 and anchor 772 may include a biocompatible polymer which bondstogether with the application of energy, such as ultrasonic energy.

It is also contemplated that a washer or spacer may be utilized with thefixation device of FIG. 51. The washer may be placed over the cap post778 and positioned against the bottom side of the cap lid 782.Therefore, as the cap 780 is being screwed into the anchor 772, thewasher prevents the spinning cap 782 lid from damaging the tissue. Thewasher would remain stationary relative to the tissue, while the cap lid782 would spin against the washer. As illustrated in FIG. 50, thesurface of the washer that contacts tissue or an implant may beconfigured with a plurality of projections that can help grip the tissueor implant material.

Like the embodiment described above, the fixation device 790 of FIG. 52includes a permanent type of mechanical locking. The anchor 792, asshown, is similar to the anchors previously described; however, theanchor bore 794 includes a plurality of circumferential grooves 796disposed in the wall of the bore. The bore grooves 796 are configured toreceive circumferential ribs 798 disposed on the exterior surface of thecap post. The cap 800 is insertable within the anchor 792 by pushing thecap post into the anchor bore 794. In addition, to enhance the holdingpower of the fixation device 790, the cap 800 and anchor 792 may includea biocompatible polymer which bonds together with the application ofenergy, such as ultrasonic energy. The configuration of the mechanicallock of this embodiment may be altered so that the cap post has aplurality of groves or indentations, which the anchor bore has aplurality of projections or ribs.

FIGS. 53 and 54 illustrate yet another embodiment of a fixation device802 of the invention. The anchor 804 may include a material which ispolymeric, hydrophilic, expandable, compressible, or combinationsthereof. The anchor 804 may be made of such material or the material maybe mixed within or coated on the anchor. For example, the anchor mayinclude, or be made of, a hydrophilic material which expands when itcomes in contact with liquid. The hydrophilic material may be desiccatedbody tissue, foam, or a polymer. A hydrophilic anchor 804 is shown inFIG. 53 in a normal, non-expanded configuration. Body fluid is absorbedby the anchor 804, and it swells to a larger diameter or greater size.The expansion of the anchor results in an interference fit between theanchor 804 and the bone, tissue or material 806 in which it is disposed,thereby providing frictional forces on the outer surface of the anchorto increase its gripping force. Projections 808 may be disposed on theouter surface of the anchor 804 to further increase the frictionalforces that hold the expanded anchor in place.

In its initial, non-expanded configuration, the anchor 804 andprojections 808 may fit within the bore of the anchor. In the expandedor swelled configuration, the projections 808 may be forced into thesurrounding tissue to thereby help lock the anchor 804 to the tissue806. The projections 808 may be small pointed nubs, angled ramps, raisedridges, spikes, circumferential rings, and similar configurations. Theprojections 808 illustrated in FIGS. 53 and 54 are angled ramps orientedin opposite directions so that the proximal ramps prevent the anchorfrom being pulled out of the tissue while the distal ramps prevent theanchor from being pushed farther into the tissue.

In another example, the anchor 804 may include, or be made of, acompressible-expandable material, such as foam, gel, or a polymer. Priorto insertion of the anchor 804 into the drilled passageway in thetissue, the anchor and projections may be compressed into a smallerdiameter or size. The compressed anchor 804 may be positioned in thetissue as shown in FIG. 53 and then allowed to expand to its normal,expanded configuration as seen in FIG. 54.

It should be noted that regardless of whether the anchor includes ahydrophilic material or a compressible-expandable material, the cap 810may be secured to the anchor 804 by a mechanical lock, by thermalbonding, or by a combination of mechanical locking and thermal bonding.Also, the cap 810 may be secured to the anchor 804 by the expandingfeature of the anchor 804. Not only may the anchor expand radiallyoutward to increase overall diameter size, but it may also expandradially inward into the cap post 812 thereby enhancing the lockingstrength between the cap and anchor. This inward expansion of the anchor804 against the cap 810 may be the sole means for fastening the cap 810and anchor 804 or may be utilized in conjunction with mechanical lockingor thermal bonding as described herein.

For example, an anchor 804 of the present invention may be made of amaterial which expands hydrophilically or inherently after compressionand which can be thermally welded to a polymer in the cap. The expansionof the anchor 804 locks the anchor to tissue 806 and provides additionalholding power of the cap 810 and anchor 804 in conjunction with athermal weld. As another example, the anchor 804 could have a coatingwhich expands hydrophilically or inherently after compression. Thecoating may be placed over a polymer material which may not expand butwhich may be thermally weldable to the cap 810. In this example, theanchor 804 may not expand inwardly against the cap 810; but instead athermal weld, and if desired a mechanical lock, may be used to securethe cap and anchor.

As best seen in FIG. 54, an energy source is positioned through thecannulated cap 810 and anchor 804. Energy, such as ultrasound, heat, orRF, is transmitted to the fixation device to bond the cap and anchor.The energy source 814 shown in FIG. 54 includes a lid-contacting surface816. Therefore, because the anchor 804 includes projections 808 to helpprevent the anchor 804 from being pushed further into the tissue, aforce can be applied to the cap lid 818 through the energy source tothereby firmly squeeze or pinch the tissue or implant 820 between thecap lid 818 and bone 806.

FIGS. 55 and 56 illustrate an exemplary embodiment of the fixationdevice having an expandable anchor 822 without projections disposed onthe outer surface of the anchor. Instead, the anchor 822 has asubstantially smooth exterior surface and a non-expanded diameter whichis equal to or slightly less than the diameter of the drilled passageway824 in the bone 826. As seen in FIG. 55, the anchor 822 in itsnon-expanded configuration is inserted into the bone 826 such that thetrailing end or proximal end of the anchor 822 is positioned at orslightly distal to the bottom surface of the cortical bone 828. In thisorientation, the anchor 822 can expand into the cancellous bone 826, andthe trailing end of the expanded anchor 822 will be adjacent to theunderside of the cortical bone 828. In FIG. 56, an overlap region 830 isshown where the expanded anchor 822 and cortical bone 828 overlap eachother. With the anchor 822 expanded and orientated in this way, theanchor 822 is held firmly in the bone thereby preventing the anchor frombeing pulled out.

To secure the cap 832 to the lid 834, an energy source 836 may bepositioned through the cannulated cap and anchor. Energy, such asultrasound, heat, or RF, may be transmitted to the fixation device tobond the cap 832 and anchor 822 when the fixation device includes athermally bondable material. Alternatively, or additionally, theexterior surface of the cap post 838 and the inside wall of the anchorbore may include a mechanical lock. Alternatively, or additionally, theanchor may expand inwardly to hold the cap relative to the anchor.

FIGS. 57A-57D illustrate an exemplary method of implanting the fixationdevice to secure tissue to bone. Shown in FIG. 57A, an anchor 840 isinserted into a drilled passage 842 in a bone, tissue, or implant 844.The anchor 840 includes helical threads 846 to form a mechanical lockbetween the anchor 840 and bone, tissue, or implant 844. To furtherstabilize the anchor 840, at least a portion of the anchor 840 may beexpanded within the bone passage. The tissue 848 may be speared with acap post 850 and an insertion instrument 852 which may be disposed inthe cannulated cap. As previously described, the insertion instrument852 or guide wire may have a pointed distal tip which helps create asmall hole in the tissue. Because the cap post 850 includes a chamfereddistal portion, the insertion of the cap post 850 through the tissue 848stretches the small hole created by the insertion tool and preventsundesired excessive tearing of the tissue 848.

In FIG. 57B, the cannulated cap 854 and insertion instrument 852 arealigned with the anchor 840, and the cap post 850 is inserted into theanchor bore. The insertion tool 852 is pushed distally to squeeze thetissue 848 between the cap lid 856 and anchor/bone. The cap post 850 maybe inserted partially into the anchor bore if thick tissue is beingfastened, or the cap post 850 may be inserted further toward the bottomof the anchor bore when a thin piece of tissue 848 is being fastened. Inthe latter configuration, the anchor 840 may include a channel extendingbetween the distal tip and the bottom of the bore to accommodate thepointed distal tip of the insertion instrument 852. Regardless of thedepth of insertion of the cap 854 into the anchor 840, a mechanical lockmay be engaged to temporarily or permanently secure the cap 854 to theanchor 840.

Precise depth placement of the cap in the anchor may be required forcertain applications. For example; in rotator cuff repair, the typicalthickness of a healthy rotator cuff is 5 to 10 mm. Therefore, to providea secure fixation of the rotator cuff to the bone, a gap between the lidand anchor/bone may be about 2 to 3 mm. To obtain a consistent gap, theanchor depth adjustment on the insertion instrument could be manuallyset. The instrument could have gradations that correspond to the depthof the anchor's top surface into the bone. Also, the depth that the capmay be inserted may be controlled with the insertion tool by adjustingthe spacing of the end effector and sheath covering the end effector.The sheath may be marked with indicia or have a window through which thecap can be seen. Furthermore, the cap itself may have a mechanical stoppreventing the cap from progressing too deep into the anchor. Themechanical stop may be a stepped post shaft.

Moreover, the use of a mechanical lock, such as circumferential ribs andcorresponding grooves, may be strategically placed on the fixationdevice such that each locking or snapping of a rib in a grooverepresents a known distance the cap has traveled in the anchor. Byknowing the distance the cap has been inserted in the anchor, the gapdistance can be determined. The desired gap distance may also be presetinto the energy source generator and controlled with closed loopfeedback by a position sensor such as an LVDT. This could measure theamount the cap melts into the anchor by stopping the energy when thedesired gap is achieved. Finally, for a mechanical locking cap, the capinsertion instrument may include markings denoting depth of insertion.

The cap insertion tool 852 is removed in FIG. 57C and an energy source858 is inserted into the cannulated cap 854 and anchor 840. Energy isapplied to the fixation device to thermally bond the cap and anchortogether. Thermal bonding may be in addition to mechanical locking ormay be the sole means for bonding the cap and anchor. FIG. 57Dillustrates the fixation device completely implanted. The tissue 848 isheld firmly relative to the bone 844. A portion of the tissue betweenthe cap lid 856 and the anchor 840 and bone 844 is being compressed.

Referring now to FIG. 58, two types of fixation devices of the presentinvention are shown with a bone plate 860 to stabilize a fractured bone862. While the following example depicting a use of the presentinvention involves only two devices and a plate, it is contemplated thattwo or more fixation devices may be employed. Also, instead of a boneplate 860, a tissue grail such as a bone graft may be secured to a bone.As shown in FIG. 58, two anchors 864 are inserted into the bone 862. Abone plate 860 is positioned adjacent the bone 862 with two holes in theplate aligning with the two anchors 864. A cap 866 is then insertedthrough the bone plate 860 and into the each of the anchors 864. Thecaps 866 may be secured to the anchors 864 by mechanical locks, bythermal bonding, by expansion, or by combinations thereof.

The design of the post of the cannulated cap permits the use of a boneplate 860 which does not require pre-formed fastening holes. Such aplate may be made from a polymeric material that is strong enough tostabilize the bone, yet can still be penetrated by the distal tip of theinsertion tool and chamfered distal portion of the cap post. In thisembodiment, the location of the drilled passageways in the bone forplacement of the anchors does not need to be aligned with pre-existingholes in the plate, giving the physician greater discretion as to theplacement of the fixation devices.

Another embodiment of the present invention is illustrated in FIG. 59.The anchor 870 and cap post 872 of this embodiment may utilize any ofthe various structural features described herein. The anchor 870 and cappost 872 may be secured together mechanically, thermally, throughexpansion, or combinations thereof. The cap lid 874 includes a lumen 876extending radially therethrough. The lumen 876 may be generallyperpendicular to and extend through the longitudinal axis of the cap.The lumen 876 may be dimensioned to receive a portion of a suture, Kwire, cable, or similar fastening member. The suture when placed throughthe lumen of the lid provides for a secondary fixation of tissue and/oran implant. For example, the cap may be inserted into the anchor 870 tosecure a bone plate to a bone. For additional reinforcement, a suturemay be positioned through the lumen 876 of the lid, wrapped around thebone and plate, and secured.

FIG. 60 shows yet another embodiment of the fixation device of thepresent invention. Unlike a cap lid having a lumen for the passage of asuture as described above for FIG. 59, the cap lid 880 of FIG. 60includes a suture or wire 882 molded into or attached to the lid 880.The suture 882 may be connected on a side surface or the top surface ofthe lid. The suture 882 extends from the lid 880 and is positionableabout tissue and/or an implant. A portion of suture is also positionablebetween the underside of the lid 880 and the upper surface of the anchor884. In this configuration, an anchor 884 may be inserted into tissueand the cap 880 is then positioned in the anchor bore but not yet weldedto the anchor. A portion of the suture 882 may be sandwiched between thecap lid 880 and anchor 884, then the cap is secured to the anchor eithermechanically, thermally, via expansion, or combinations thereof. As seenin FIG. 60, the suture 882 may extends from one side of the cap, can belooped around tissue or an implant, and may be returned generally to theopposite side of the cap 880 to be pinched and secured to the fixationdevice.

FIG. 61 depicts another embodiment of a fixation device 890 with asuture 892. A lumen 894 extends radially through the anchor 896 at alocation intermediate between the leading and trailing ends of theanchor. The lumen 894 may extend perpendicular to and through thecentral longitudinal axis of the anchor 896. A groove 898 disposed inthe threads or outer surface of the anchor 896 runs generally parallelto the longitudinal axis of the anchor and extends from one end of thelumen 894 to the trailing or proximal end of the anchor 896. Anothergroove 898 disposed in the threads of the anchor also runs generallyparallel to the long axis of the anchor but extends from the other endof the lumen 894 to the proximal end of the anchor 896. A suture 892 ispositionable within the lumen 894 and grooves 898 of the anchor 896. Thecap 900 of the fixation device 890 may be similar to the cap describedin FIG. 52 which has a plurality of circumferential ridges disposed onthe post. The anchor bore may have a plurality of correspondingcircumferential grooves disposed in the wall of the bore. The cap post902 has the additional feature of a cut out or notch 904 located at thedistal tip. The notch 904 is dimensioned to receive one or more sectionsof suture.

In use, a suture 892 is positioned through the radially extending lumen894 and grooves 898 in the anchor 896. The anchor 896 is then insertedin tissue such that two sections of the suture 892 extend from theanchor/tissue. The suture sections are secured to or around tissue or animplant such that a portion of one or both suture segments is positionedover the proximal opening of the anchor bore. The cap 900 is alignedwith the anchor bore, and the notch of the cap 904 is placed about oneor both of the suture segments 892. The cap 900 is moved into the anchorbore while maintaining the suture segment(s) in the notch 904 of thepost. When fully seated, the circumferential ridges of the post matewith the circumferential grooves of the anchor bore, and one or bothsuture segments are pinched/held between the cap post and the outer wallof the anchor bore.

In FIG. 62, another exemplary embodiment of the present invention isillustrated. The anchor 910 in this embodiment includes a post 912extending from the proximal or trailing edge of the anchor. The post 912may include a pointed proximal tip to permit the post to penetratethrough and/or extend beyond tissue or an implant. Preferably, theproximal tip does not include a blunt end so that the tissue or implantis not unnecessarily torn or damaged. The cap 914 includes a lid 916 andpost 918 like previous embodiments. However, in this embodiment, thepost 918 includes a bore 920 which is configured to receive the anchorpost 912. The cap post 918 may include a chamfered leading edge for easypenetration of the cap post through tissue or an implant. The cap 914and anchor 910 may be cannulated to allow insertion of a guide wire oran energy source.

The fixation device of FIG. 62 may be used for the fixation of tissue oran implant as follows. The anchor 910 is inserted in tissue, such asbone, with the anchor post 912 extending from the bone. The anchor 910may include external helical threads 922 which permit the anchor 910 tobe screwed into the bone. Additionally, or alternatively, the anchor 910may be held in the bone via expansion of the anchor. Tissue or animplant is aligned over the anchor and pressed over the anchor post 912.The cap 914 of the device holds the tissue to the bone by placing thecap post bore 920 over and about the anchor post 912. The cap 914 andanchor 910 may be secured to each other by mechanical means, thermalbonding, via expansion, or combinations thereof. It is furthercontemplated that implantation of the device may be performed over aguide wire positioned in the cannulated cap and anchor.

Referring to the embodiment shown in FIGS. 63A and 638, the anchor 930includes two posts 932. The anchor 930, if desired, may include two ormore posts 932. The posts may be parallel to or at an angle to thelongitudinal axis of the anchor. In FIG. 63A, the two posts 932 areangled away from each other. In this configuration the fixation devicemay provide an enhanced stabilization and fixation of tissue or animplant. The cap lid 934 may be designed to remain generally parallel tothe top surface of the anchor 930, or they can remain perpendicular tothe cap post 936 and be at an angle relative to the top surface of theanchor 930. The method of implanting the embodiment of FIGS. 63A-B issimilar to the implantation of the fixation device of FIG. 62. However,multiple caps are inserted onto the multiple anchor posts by way ofmechanical locks, thermal bonding, anchor expansion, or combinationsthereof.

As shown in FIGS. 64A and 64B, another exemplary embodiment includes ananchor 940 having two bores 942. The anchor 940, if desired, may includetwo or more bores. The bores 942 may be parallel to, at an angle to,and/or offset from the longitudinal axis of the anchor 940. The cap 944includes a post 946 connected with a lid 948. The cap post 946 isconfigured for insertion into one of the bores 942 of the anchor 940.The distal tip of the cap post is pointed for penetration through tissueor an implant. The cap lid 948 may be designed to remain generallyparallel to the top surface of the anchor, or it can remainperpendicular to the cap post and be at an angle relative to the topsurface of the anchor. The method of implanting the embodiment of FIGS.64A-B is similar to the implantation of the fixation device of FIGS.63A-B. However, multiple cap posts that penetrate the tissue or implant,are positioned in the anchor bores, and are secured to the anchor by wayof mechanical locking, thermal bonding, anchor expansion, orcombinations thereof.

Referring to FIG. 65A, another exemplary fixation device is illustrated.The anchor 950 includes two slots 952 disposed in the wall of theanchor. The slots 952 extend from the trailing end of the anchor to anintermediate area between the trailing and leading ends of the anchor950. The slots 952 extend completely through the anchor wall. Theexterior surface of the anchor includes protrusions 954 that increasethe frictional forces between the anchor and the engaging tissue. Anyconfiguration or structure described herein may be used to increase thefrictional forces. As illustrated in FIG. 65A-B, the protrusions 954 maycomprise a plurality of circumferential ribs. The cap 956 of thefixation device includes a lid 958 and post 960. The cap post 960 isconnected with the lid 958 and tapers in diameter as the post extendsfrom the lid 960. The distal tip of the cap post 960 includes achamfered point for piercing and stretching tissue.

In use, the anchor 950 is inserted in tissue such as bone or in animplant material. The anchor 950 may be inserted in a pre-drilledpassageway in the bone or may be include a self-tapping tip and notrequire a pre drilled hole. Tissue or an implant may be positioned overthe anchor 950, and the cap 956 can be inserted into the anchor bore 962through the tissue or implant. As seen in FIG. 658, the cap post 960 isinserted into the bore of the anchor. Because the cap post 960 istapered, as it is pushed into the anchor bore 962, portions of theanchor 950 are separated as the slots bias outward. In thisconfiguration, the anchor is locked into the bone with thecircumferential ribs and by the outwardly biased anchor portions. Ifmovement of the anchor wall is restricted by bone, tissue, or animplant, then the resistive forces may instead be increased at insertionof the cap post 960 imparts outward pressure on the anchor walls. Thecap and anchor may be bonded together by mechanically locking, thermalbonding, via expansion, or combinations thereof. The cap 956 and anchor950 may be cannulated to receive a guide wire, insertion tool, and/orenergy source.

In FIG. 66, an embodiment similar to FIGS. 65A-B is shown, except theexterior surface of the anchor 964 is substantially smooth. The anchor964 also includes two or more slots 966 disposed in the anchor wall. Itis contemplated that the anchor may include two, three, four, five, six,or more slots. In use, the anchor 964 is inserted in bone such that thetrailing or proximal end of the anchor is positioned just under thebottom surface of cortical bone. The cap 968 is inserted through tissueor an implant. The tapered cap post 970 is moved distally into theanchor bore 972 forcing the anchor segments separated by the slots tooutwardly bias. The biased anchor segments penetrate into thesurrounding cancellous bone, and the proximal ends of the anchorsegments overlap the cortical bone. In this configuration the anchor isprevented from being pulled out of the bone since the proximal ends ofthe anchor segments come in contact with the underside of the corticalbone. The cap and anchor may be bonded together by mechanical locking,thermal bonding, via expansion, or combinations thereof. The cap andanchor may be cannulated to receive a guide wire, insertion tool, and/orenergy source.

Referring to FIGS. 67 and 68, a triangulation fixation device includestwo anchors 980, 982 with a suture, cable, or band 984 attached to theanchors. A primary anchor 980 is generally cylindrical in shape andincludes a channel extending therethrough at an angle to the centrallongitudinal axis of the anchor. The channel is configured for receivinga secondary anchor 982. The secondary anchor 982 includes atissue-piercing and tissue-stretching leading tip. The anchors may becannulated to allow insertion of a guide wire, insertion tool, and orenergy source. The band 984 is connected to both the primary andsecondary anchors 980, 982. The band 984 may be pivotably or rotatablyattached to the anchors so that the anchors can be inserted in tissuewithout the band being twisted or tangled.

To implant the triangulation fixation device, a primary passageway isdrilled in tissue such as bone. The diameter, depth, and angle of theprimary passageway are predetermined based on the configuration of theprimary anchor 980. A secondary passageway is drilled in the bone whichintersects the first passageway. The diameter, depth, and angle of thesecondary passageway are predetermined based on the configuration of theprimary and secondary anchors 980, 982. The primary anchor 980 is firstinserted into the primary passageway. The primary anchor 980 may besecured within the passageway by helical threads 986, by expansion, orby other suitable means disclosed herein. The secondary anchor 982 ismoved through tissue with the leading tip and positioned in thesecondary passage. The secondary anchor 982 is inserted into the channelof the primary anchor 980 and fastened to the primary anchor 980 by amechanical lock, thermal bonding, expansion, or combinations thereof.Locking the anchors together tensions the band interconnected betweenthe anchors thereby fastening the tissue 988 to the bone.

Another embodiment of a triangulation fixation device is shown in FIGS.69 and 70. This embodiment is similar to the one previously describedexcept the anchors 990, 992 do not have threads disposed on their outersurfaces, i.e., the anchors have smooth sides. A suture, band, or otherflexible material 994 is disposed between the primary and secondaryanchors 990, 992. The suture 994 may be attached to the trailing end orthe side of each anchor 990, 992. The primary anchor 990 is generallycylindrical in shape and includes a pocket or receptacle therein at anangle to the central longitudinal axis of the anchor. The pocket orreceptacle is configured for receiving a distal portion of the secondaryanchor 992. The secondary anchor includes a tissue-piercing andtissue-stretching leading tip. The chamfered leading portion of thesecondary anchor may 992 also act as a conical energy director to assistin thermal bonding. The anchors may be cannulated to allow insertion ofa guide wire, insertion tool, and or energy source. The cannulas in theanchors may be congruent to the longitudinal axis of the anchors oroffset from the long axis of the anchors so as to not interfere with thesuture or band 994.

To implant the triangulation fixation device of FIGS. 69 and 70, aprimary passageway is drilled in tissue such as bone. The diameter,depth, and angle of the primary passageway are predetermined based onthe configuration of the primary anchor 990. A secondary passageway isdrilled in the bone which intersects the first passageway. The diameter,depth, and angle of the secondary passageway are predetermined based onthe configuration of the primary and secondary anchors 990, 992. Theprimary anchor 990 is inserted into the primary passageway, and then thesecondary anchor 992 is moved through tissue with the leading tip andpositioned in the secondary passage. Insertion of the anchors may beperformed with a suitable insertion instrument. The secondary anchor 992is inserted into the pocket or receptacle of the primary anchor andfastened to the primary anchor by a mechanical locking, thermal bonding,expansion, or combinations thereof. As shown, an ultrasonic end effectormay be used to bond the anchors together. Locking the primary andsecondary anchors together helps prevent the anchors from being pulledout of the bone.

The triangulation fixation devices described above included a primaryanchor having a channel, pocket or receptacle in which the secondaryanchor is positioned and secured. It is also contemplated that theanchors may be attached to each other by way of hooks, loops, latches,or similar mechanical means. For example, one anchor may have a hook onits distal end while the other anchor may have a hook or loop at itsdistal end. The anchors may be positioned in their respective drilledpassageways in bone and are connected to each other with the hook/loopcombination. In another example, the primary anchor may have a hook/loopat its midsection while the secondary anchor may have a hook/loop at itsdistal end. The primary and secondary anchors may be secured together bysuch a mechanical means.

The suture or band of the triangulation fixation device may be tensionedto provide fixation of tissue and/or an implant. An energy source may beused to shrink the suture or band to an appropriate tension or length.The energy source may be one previously described. Alternatively, oradditionally, the band (or anchors) may include shape memory material,such as Nitinol®. As this material is heated with a thermal probe orwith natural body heat, the device could flex or bend to self-tighten orlock in tissue.

Referring now to FIG. 71, another embodiment of a fixation device isillustrated. The anchor 1000 may have helical threads 1002 disposed onits outer surface for holding the anchor in tissue, such as bone. Thecap 1004 includes a post 1006 attached to a lid 1008. Helical threads1010 are disposed on the exterior surface of the cap post 1006. Thethreads on the cap post and anchor may be the same or different size.Also, the threads on the cap post and anchor may both be right-handedthreads or may both be left-handed threads. Furthermore, the threads onone may be right-handed, while the threads on the other may beleft-handed. The cap also includes a snap ring 1012 that allows the cap1004 to be locked into the anchor 1000 preventing it from coming outafter being screwed into the anchor bore. The snap ring 1012 on the cappost 1006 mates with a groove in the wall of the anchor bore. As shownin FIG. 71, the snap ring 1012 may be a circumferential ring that istapered at its leading portion and has a shoulder at its trailingportion. The snap ring 1012 may extend partially around or entirelyaround the cap post 1006. The groove in the anchor bore may have acorresponding configuration to receive the snap ring. The taperedleading portion of the snap ring 1012 allows the ring to snap into thegroove, and the shoulder prevents the ring (and cap) from being pulledout of the anchor.

The cap 1004 and anchor 1000 may be cannulated to receive a guide wire,an insertion instrument, and/or an energy source. As illustrated, aninsertion tool is disposed in the cannulated cap. The insertion tool1014 may include a piercing tip 1016 for penetration through tissue. Theinsertion tool 1014 may also include a mating means for temporarilyconnecting the tool and the cap. Examples of mating means between theinsertion tool and cap may include a flat-shaped, square-shaped,rectangular-shaped, hexagonal-shaped, or octagonal-shaped projection anda corresponding socket.

FIG. 72 illustrates another exemplary embodiment of a fixation deviceutilizing features of the invention. The device includes an anchor 1020having a post 1022 connected with a body 1024. The anchor body 1024 mayinclude means for securing the anchor body to the bone, such as helicalthreads, expansion, or other suitable means. The anchor post 1022 isgenerally cylindrical and has a bore extending therethrough, at leastthrough the proximal end of the post. The anchor post 1022 may include aretaining ring or snap ring I 026 disposed on the outer surface of theanchor post. The retaining ring 1026 may be a circumferential projectionor rib. The device further includes a tissue-piercing pin 1028 which maybe insertable and removable from the anchor post bore. The pin 1028 mayhave a distal portion configured for insertion into the bore of theanchor post 1022. The proximal portion of the pin may be generallyconical and have a point at the proximal tip. The tip and conical shapeare designed to pierce and stretch tissue. The pin 1028 may be made ofor include a metallic, composite, ceramic, or polymeric material. InFIG. 72, the pin 1028 shown is made of stainless steel. The device alsoincludes a cap 1030 being generally disk shaped. The cap 1030 includesan orifice disposed therethrough which is dimensioned to receive theanchor post 1022. The orifice has a diameter which is equal to orslightly greater than the diameter of the anchor post. However, theorifice diameter is not greater than the diameter of the retaining ringon the anchor post.

As illustrated in FIG. 73, the anchor is inserted in tissue 1032, suchas bone. A passageway may be drilled in the bone and the anchor bodyinserted therein. Or, the anchor 1020 may be self-tapping and thereforenot require a pre-drilled passageway. The anchor 1020 may be secured tothe bone 1032 by mechanical means such as threads, expansion, or similarmeans. With the anchor post 1022 extending from the bone, the pin isplaced in the anchor bore. Tissue 1034, such a rotator cuff, or animplant, such as a bone plate, may be positioned over the anchor abovethe pin. The tissue or implant 1034 is moved toward the bone such thatthe pointed and chamfered end of the pin pierces the tissue/implant andthe anchor post penetrates through the tissue/implant. The pin may beremoved from the anchor post bore by a magnetic instrument, graspers,claws, or other suitable surgical tool. The cap 1030 may be placed overthe anchor post 1022. The cap 1030 is moved toward the anchor bodythereby squeezing and fastening the tissue/implant 1034 toward the bone1032. The cap 1030 may be held to the anchor post 1022 by the retainingor snap ring 1026. Alternatively, or additionally, the cap and anchormay be connected together by mechanical locking, by expansion, bythermal bonding, or combinations thereof. If thermal bonding between thecap and anchor is desired, an energy source, such as a resistive heater,ultrasonic staking instrument, or other suitable energy sources, may beused.

The fixation device of FIGS. 72 and 73 can be used with a guide wire oran insertion instrument as previously described with other fixationdevice embodiments. The anchor, cap, and/or pin may be cannulated toreceive the wire or instrument. In this configuration, the fixationdevice may be placed with precision within tissue or an implant. Also,the fixation device of FIGS. 72 and 73 may be used with a suture. Thesuture may be used to fasten tissue and/or implant and then insertedthrough the cap and secured. The suture may be positioned between thecap and anchor to be secured. Furthermore, the suture may be molded intoand extend from the cap and/or anchor. It is contemplated that thedescriptions and features of the fixation devices and sutures of FIGS.59-61 apply to the fixation device of FIGS. 72 and 73.

In a related invention, the fixation of tissue may be accomplished byheating collagen in tissue under defined pressure to create spot welds,i.e. tissue welding or protein welding. This fixation may be in additionto or separate from the previously described fixation devices. Heatingof collagen in tissue may be done with an energy source such asultrasonic energy, thermal energy, or other energy source previouslymentioned. In addition, metallic particles, such as iron oxide, may beplaced on the tissue to assist with heating.

In another related invention, laser tissue welding may be used inconjunction with or separate from the fixation devices. Laser tissuewelding is a sutureless method of wound closure that may be used onnerves, skin, muscles, ligaments, tendons, bone, and arterialanastomoses. After heating generated by laser exposure, a glue is formedbetween tissue edges that forms a weld upon cooling. With the use oflaser welding, there may be no foreign body reaction and less scarformation. Laser welding when used with an artificial biomaterial mademostly of elastin and fibrin to weld tissue allows a broad surface areafor welding. Also, the use of a pulsed diode laser may be used tomaintain thermal confinement and therefore minimize excess heating.

In yet another related invention, tissue may be approximated ormanipulated with an instrument utilizing suction or negative pressure.For example, a torn rotator cuff may require stretching or repositioningback to its anatomically correct position then may require fixation tobone using a fixation device described herein. The manipulation of therotator cuff to its correct location may be achieved by placing thedistal portion of an instrument against the rotator cuff activating avacuum or sucking force at the distal end of the instrument, and pullingthe rotator cuff into position. The distal end of the instrument mayinclude a suction port, a suction cup, a suction cup with a suction porttherein, or other similar negative pressure means.

The fixation devices and above-mention related devices may be used incombination with each other. For example, a torn rotator cuff may needto be refastened to bone, or cartilage within a joint, such as the knee,may need to be repaired. The negative pressure instrument may be used tograb and move the cuff/cartilage into proper position. A fixation devicemay be implanted to temporarily or permanently secure the tissue tobone. Tissue or protein welding may be performed to provide a thoroughbonding of the cuff/cartilage and bone.

The present invention also may be used in additional types ofintracorporeal welding devices and methods. Referring now to FIGS. 74Aand 74B, a fastener 1040 includes a cap 1042 and anchor 1044. Thefastener 1040 may be made of thermoplastic material. The anchor 1044 isgenerally tubular shaped with a circular flange 1046 attached to theproximal end. Four slots 1048 (two shown) are disposed longitudinallyfrom the distal end of the anchor 1044. The four slots 1048 divide theanchor into four biasing prongs 1050. The prongs 1050 bias or hinge fromgenerally the proximal end of the anchor 1044. Each biasing prong 1050includes an outwardly projecting ridge 1052 and an inwardly projectingridge 1054. The cap 1042 includes a post 1056 and a lid 1058 connectedto the proximal end of the post 1056. Both the cap 1042 and anchor 1044may include a tissue-piercing distal tip.

In use, the anchor 1044 may be placed in tissue, such as bone.Initially, the prongs 1050 of the anchor 1044 may not be biased outwardduring this step. Next, the cap post 1056 is inserted through an implantor tissue and positioned within a bore of the anchor 1044. When the cappost 1056 contacts the inwardly projection ridges 1054 of the prongs1050, the prongs will be urged to move radially outward. The outwardlyprojecting ridges 1052 of the prongs 1050 are driven into surroundingtissue to thereby prevent the anchor from being pulled out of the bone.Once the cap is seated in its desired position, ultrasonic energy may beapplied to the fastener 1040 to weld the anchor 1044 and cap 1042together.

In FIGS. 75A and 75B, a fastener 1060 includes a cap 1062 and anchor1064. The fastener 1060 may be made of thermoplastic material, such asPEEK or PLLA. The anchor 1064 is generally tubular shaped with circularflange 1066 attached to the proximal end. Four slots 1068 may bedisposed longitudinally from the proximal end of the anchor 1064. Withineach slot 1068 is a longitudinal barb 1070. The distal end of each barb1070 is attached to the anchor 1064 while the proximal portion of thebarb is free from attachment to the anchor and can be angled generallyproximally and radially outward, i.e. between 30 and 60 degrees from thecenterline of the anchor. The cap 1062 includes a post 1072 and a lid1074 attached to the proximal end of the post. The post 1072 includesfour wedge members 1076 attached to the exterior surface and spacedaround the post 1072 such that each wedge member 1076 aligns with a slot1068 in the anchor 1064. Each wedge member 1076 includes an angled facewhich is angled about the same as the proximal portions of the barbs1070. Both the cap 1062 and anchor 1064 may include a tissue-piercingdistal tip.

To implant the fastener of FIGS. 75A and 75B, the anchor 1064 may beinserted in tissue, such as bone. During insertion, the proximalportions of each barb 1070 which extend beyond the exterior surface ofthe anchor will flex or bend until they are forced radially inward asufficient amount so that the anchor 1064 may fit within a passageway inthe bone. The cap 1062 is then inserted through an implant or tissue andpositioned in the bore of the anchor. The wedge members 1076 on the cappost 1072 may then slide into the slots 1068 of the anchor 1064. As thecap 1062 is seated, the wedge members 1076 of the cap force eachlongitudinal barb 1070 radially outward moving the proximal portion ofeach barb into surrounding tissue to secure the fastener in place.Ultrasonic energy may be applied to the fastener 1060 to secure the capand anchor together.

FIGS. 76A and 76B illustrate another embodiment of a fastener 1080 ofthe present invention. The fastener 1080 is similar to the fastener ofFIGS. 74A and 74B except that the anchor 1082 includes two slots 1084and two biasing prongs 1086. The method of implanting the fastener ofFIGS. 76A and 76B is also similar to the method of inserting thefastener of FIGS. 74A and 74B.

Referring now to FIGS. 77A and 77B, a fastener 1090 includes a cap 1092and anchor 1094. The fastener 1090 may be made of thermoplasticmaterial. The anchor 1094 is generally tubular shaped with a circularflange 1096 attached to the proximal end. Two slideable hooks 1098 maybe disposed in the anchor 1094 and extend from the bore of the anchorand through channels in the anchor wall. The hooks 1098 are generallycurved at least at the distal ends. The cap 1092 includes a post 1100and a lid 1102 connected to the proximal end of the post. The post 1100includes a shoulder 1104 formed by two different diameters of the post.The shoulder 1104 is configured for contact with the proximal ends ofthe hooks 1098 in the anchor 1094. Both the cap 1092 and anchor 1094 mayinclude a tissue-piercing distal tip.

In use, the anchor 1094 may be placed in tissue, such as bone. Theslideable hooks 1098 are substantially disposed in the anchor, i.e.little if any of the hook 1098 extends beyond the exterior wall of theanchor 1094 during insertion. Next, the cap post 1100 is insertedthrough an implant or tissue and positioned within the bore of theanchor 1094. When the shoulder 1104 of the post 1100 contacts theproximal ends of the hooks 1098, the hooks are moved distally andoutwardly into surrounding tissue preventing the anchor 1094 from beingpulled out of the bone. Once the cap 1092 is seated in its desiredposition, ultrasonic energy may be applied to the fastener to weld theanchor and cap together.

The fastener 1110 illustrated in FIGS. 78A and 78B also includes a cap1112 and anchor 1114. The fastener 1110 may be made of thermoplasticmaterial. The anchor 1114 is generally tubular shaped with a circularflange 1116 attached to the proximal end. Two or four slots 1118 may bedisposed in the anchor wall and extend from the proximal end of theanchor. A folding member is disposed in the bore of the anchor andthrough the slots. The folding member includes a proximal ring 1120, adistal ring 1122, and two or four crimping arms 1124 connected betweenthe rings 1120, 1122. The folding member may be made of metal,thermoplastic, or other suitable material. The cap 1112 includes a post1126 and a lid 1128 connected to the proximal end of the post. The cappost 1126 includes a shoulder 1130 formed by two different diameters ofthe cap post 1126. The shoulder 1130 is configured for contact with theproximal ring 1120 of the folding member. Both the cap 1112 and anchor1114 may include a tissue-piercing distal tip.

The anchor 1114 may be placed in tissue, such as bone. During placementin bone, the crimping arms 1124 are substantially straight and theproximal ring 1120 of the folding member is located at the proximal endof the anchor bore. Next, the cap post 1126 is inserted through animplant or tissue and positioned, within the bore of the anchor. Whenthe post shoulder 1130 contacts the proximal ring 1120, the crimpingarms fold 1124 or bend outwardly into surrounding tissue preventing theanchor from being pulled out of the bone. Once the cap 1112 is in itsdesired position, ultrasonic energy may be applied to the fastener toweld the anchor and cap together.

FIGS. 79A and 79B illustrate another embodiment of a fastener of thepresent invention. The fastener 1140 is similar to the fastener of FIGS.76A and 76B except that the cap post 1142 includes a tapered portion1144. The tapered portion 1144 of the post 1142 is configured to beseated against a tapered ridge within the bore of the anchor 1146. Themethod of implanting the fastener 1140 of FIGS. 79A and 79B is alsosimilar to the method of inserting the fastener of FIGS. 76A and 76B.

The fastener 1150 of FIGS. 80A and 80B is also similar to the fastenerof FIGS. 76A and 76B. However, the circular flange 1156 of the anchor1152 includes a circular rise 1154, and the underside of the cap lid1158 includes a circular recess 1160 configured for receiving thecircular rise 1154. The method of implantation is similar to methodspreviously described. During ultrasonic welding of the fastener 1150,however, the bonding between the cap 1160 and anchor 1152 is enhanced bythe increased surface area provided by the circular rise 1154 andcircular recess 1160.

FIGS. 81 and 82 illustrate another embodiment of the invention. In FIG.81, the fastener 1162 includes a rigid metallic core 1164 which isenclosed by a thermoplastic. The fastener of FIG. 82 has a polymericcore 1166 surrounded by PEEK. Although not illustrated in theseexamples, the fasteners may include a central bore for receiving thepost of an end effector.

Referring now to FIGS. 83A and 83B, a balloon fastener 1170 is shownwhich includes an elongate body 1172 and one or more balloons 1174disposed on the exterior surface of the body 1172. A passageway 1176extends from the balloon(s) 1174 and through the fastener lid 1178. Thepassageway 1176 provides open communication between the interior of theballoon(s) and the exterior of the fastener 1170. The body 1172 mayinclude a tissue-piercing tip. To implant the balloon fastener 1170, theballoon(s) may initially be in a deflated configuration andsubstantially positioned up against the exterior of the body. Thefastener 1170 is positioned in tissue with the proximal surface of thelid exposed for access by the surgeon. Once placed in its desiredposition, the balloon(s) 1174 may be filled with air, gas, liquid,powder, etc. via the passageway 1176. The balloon(s) expand againstadjacent tissue to thereby lock the fastener to the tissue. Thepassageway 1176 may be closed and sealed with ultrasonic energy andthermoplastic material.

FIGS. 84A-B, 85A-B and 86A-B illustrate living hinge fasteners. In FIG.84A, the fastener includes a main body 1180 and a toggling body 1182connected to each other with a living hinge 1184. A guide wire isslideably disposed through the main body 1180 and toggling body 1182 tomaintain the bodies in general alignment. As seen in FIG. 84B, with theguide wire removed, the living hinge 1184 normally biases the togglingbody 1182 laterally from the main body 1180. When inserted in tissue,the toggling body 1182 moves into surrounding tissue to prevent thefastener from being pulled out. An end effector 1186 may be placed inengagement with the fastener to thermally bond the thermoplasticmaterial of the main body and toggling body together.

In FIG. 85A, the fastener includes two or more toggling bodies 1190connected to the main body 1192 with two or more living hinges 1194. Asingle guidewire with a bifurcation 1196 or multiple guidewires may beused to hold the normally outwardly biased toggling bodies generallyaligned with the main body 1192. FIG. 85B shows the guidewire removedand the toggling bodies 1190 extended. An end effector 1198 may be usedto ultrasonically bond the main body 1192 to the toggling bodies 1190.

The living hinge fastener of FIGS. 86A and 86B is similar to thefastener of FIGS. 85A and 85B. However, instead of using a guidewire tomaintain the toggling bodies 1200 generally aligned with the main body1202, a sheath 1204 is disposed around the exterior surface of thefastener. To deploy the fastener of FIGS. 86A and 868, the fastenerwithin the sheath 1204 in placed in tissue. The sheath 1204 is removedand the toggling bodies 1200 normally extend outwardly into surroundingtissue. The toggling bodies 1200 may be ultrasonically welded to themain body 1202.

FIG. 87 is a photograph of a fastener of the present inventionultrasonically welded in bone. The fastener includes a post and lidconnected to the post. A hole is drilled in the bone for insertion ofthe fastener. The diameter of the hole is less than the diameter of thepost. The lid includes a small bore for an end effector. With theapplication of ultrasound and force, the fastener flows into the hole inthe bone. In FIG. 88 a fastener includes an anchor and a cap. The anchorhas slots which form a plurality of biasing prongs. With the capinserted within the bore of the anchor, the prongs move radially outwardand engage the bone thereby locking the fastener to the bone. The capand anchor are ultrasonically welded together.

The photograph of FIG. 89 shows a cut away of thermoplastic fastenersbonded within channels. The diameter of the channels is less thediameter of the posts of the fasteners. With the application ofultrasonic energy and pressure the thermoplastic material flows into thechannel, without the thermoplastic material liquefying. In FIG. 90metallic core-thermoplastic fasteners are shown bonded to thermoplasticrods. The metallic cores can be seen in the x-ray image of FIG. 91. InFIGS. 92A and 92B, PEEK and PLLA fasteners are ultrasonically bonded inbone. The bone has been cut in half to show the posts of the fastenersdisposed in channels of the bone.

Referring now to FIG. 93, a thermoplastic mesh sheet 1210 is shown. Thesheet may include openings therethrough for the passage of body fluid.Alternatively, the sheet 1210 may be free from openings to function asan impermeable membrane. The sheet may include or may be made ofthermoplastic material such as PEEK or PLLA. One or more layers ofmaterial may form the sheet. For example, an impermeable sheet may havea polymeric layer with no openings and, additionally, may include a meshlayer on one or both sides of the opening-free layer. A permeable sheetmay include one, two, three, or more mesh layers.

In FIG. 94, a mesh sheet 1212 is helically wrapped to form a tube-likestructure. The overlapping portions of the sheet 1212 may beultrasonically welded together to form a unitary structure. Thestructure may be used as a prosthetic vessel, such as a blood vessel orany other body conduit. It may also be used for tissue repair bywrapping the structure around damaged tissue. FIG. 95 shows acylindrical mesh sheet 1214. This configuration may also be used fortissue repair and/or tissue stabilization. For example, a fractured bonerequires stabilization for proper healing. A mesh sheet may bepositioned about the fractured portion of the bone. Ultrasonic energymay be used to bond the sheet to the bone. Additional energy may be usedto shrink the sheet in diameter to apply a compressive force to thefractured bone.

The cylindrical mesh sheet 1216 of FIG. 96 has been shaped using energy,such as ultrasound, resistive heating, etc. Shaping of the sheet 1216allows the surgeon to form a tailored implant. It is contemplated that anon-cylindrical sheet may be shaped using energy as well. A flat sheetmay be contoured to conform to the exterior surface of a body organ,such as the heart, stomach, the skin, a bifurcated vessel, and otherbody parts like the knee, elbow, or spine.

FIG. 97 illustrates a method of using a thermoplastic mesh sheet 1218 torepair a blood vessel 1222. An aneurysm 1224 has formed in the vesselwall. Instead of or in addition to treating the aneurysm with an emboliccoil or other known device, a mesh sheet 1218 may be wrapped about thevessel 1222 over the aneurysm region. A balloon 1220 may be positionedwithin the vessel 1222 to provide structural rigidity to the vesselwhile ultrasonic energy is applied to the mesh sheet. The sheet may bebonded to the vessel and/or itself and shrunk in diameter to slightlycompress the aneurysm. In this example, the mesh sheet 1218 may includean impermeable layer.

FIG. 98 shows another use of a thermoplastic mesh sheet 1230. Ananastomosis is shown joining two vessels. The vessels may be fastenedtogether using known surgical techniques such a suturing. Alternatively,or in addition, a thermoplastic mesh sheet 1230 may be placed betweenoverlapping portions of the vessel or at the ends of the vessels, andultrasonic energy may be applied to the sheet to bond the vesselstogether. Furthermore, a permeable or impermeable mesh sheet 1230 may beused to wrap around the anastomosis region. The sheet may beultrasonically bonded to the vessels and/or itself to create afluid/blood tight seal at the surgery site.

FIG. 99 shows a welding control box 1232. A surgeon determines theoptimum welding parameters and enters them into the control box prior towelding. An ultrasonic end effector is located on the distal end of thehandpiece. Using different control settings, such as wattage, frequency,time, etc., the end effector may be used to flow thermoplastic material,clean tissue, and/or cut tissue (i.e. osteotomy).

Welding of polymeric material to other material such as metal or plasticmay be useful in securing a tibial tray to a tibial plate in a kneereplacement component. As shown in FIG. 100, a tibial bearing surface1234 may be bonded to a metallic tibial component 1236. Instead ofhaving a manufacturer produce multiple sizes of tibial replacementcomponents, a single standard base 1236 may be made of metal and abearing surface 1234 may be bonded to the base to form a customcomponent. The size, thickness, and configuration of the bearingcomponent may be selected by a physician based on the patient's needs.The bearing component 1234 may be ultrasonically welded into or onto thebase tibial component 1236. As shown in FIG. 100, the base component1236 may have notches or channels 1238 in which the bearing component1234 can move into by the application of an energy source 1240, such asheat. The bearing surface 1234 may be further contoured or sculpted byan energy source 1240, such as heat, to create a customized surfacetailored to meet the requirements of the patient.

Alternatively, the base component 1236 may be metal with a layer orareas of polymeric material disposed thereon/therein. In thisconfiguration, instead of the bearing component 1234 being bondeddirectly to the metal, the bearing component 1234 may be bonded to thepolymer on the metal base 1236. Also, to achieve the desired height ofthe tibial component, the surgeon may insert polymeric shims aboveand/or below the bearing component. The shims may be ultrasonicallywelded in place.

Additionally, polymeric components may be bonded to joint replacementcomponents supplied by different manufacturers. It would be advantageousfor a surgeon to be able to select individual joint replacementcomponents that best fit the needs of the patient, regardless ofmanufacturer. Currently, joint replacement components are supplied as aset and can not be interchanged, mixed and matched. It is contemplatedthat the surgical welding systems of the present invention would allowsurgeons to select one component from one manufacture, another componentfrom another manufacturer, tailor one or both components, and implantthe components as a customized set. For example, for a knee replacementsystem, a surgeon could use a tibial base plate from manufacturer A anda femoral component from manufacturer B. Using polymeric material andthermal welding, a bearing surface/polyethylene may be thermally bondedto the base plate 1236. The bearing surface 1234 may be contoured andshaped to receive the femoral component. One or more layers or insertsmay be used to sequentially build up one or both of the components. Thissystem gives the surgeon more options in selecting joint components andgives greater freedom in customizing the components.

Furthermore, welding of polymeric components may be performed in situ torepair or resurface a joint replacement component, such as a shoulder,hip, knee, ankle, or intervertebral disc. For example, the bearingsurface 1234 of a knee component may become worn out over time causingthe patient pain. Instead of removing the metallic component andimplanting a new component which may be expensive and cause the patientadditional pain and require longer rehabilitation, the existing bearingsurface can be rebuilt, restored, replaced or reshaped usingthermoplastics and thermal welding. In this revision joint replacementsurgery, the existing worn out bearing surface may be prepared byremoving all, some, or none of the polymeric surface. Then, a newpolymeric component may be welded intracorporeally onto the old bearingor metallic component using ultrasound, radiofrequency, resistiveheating, etc. The new bearing surface component may be selected based onthe required thickness needed to restore the joint to its anatomicallycorrect configuration. Contouring of the bearing surface may beperformed intracorporeally or in the operating room prior to welding thenew bearing component intracorporeally.

In addition to revision surgery, it is contemplated that ultrasonicenergy and thermoplastics may be utilized with other procedures, such asrevision arthroplasty, osteomous correction, fracture fixation,cementless fixation of an implant to tissue/bone, and bone graftfixation.

If needed, multiple layers of polymeric material may be added to thedeteriorated joint component to build the joint up to the proper height(FIG. 101A-D). Rather than having an inventory of multiple inserts orcomponents all varying in different thicknesses, standard inserts may bemanufactured with a given thickness and welded together by the surgeonin the operating room to obtain the needed implant height. For example,inserts may be manufactured in 2 mm, 4 mm, and 8 mm thicknesses. Aplurality of these inserts may be selectively bonded together to form asingle insert. This may be done intracorporeally and/or within theoperating room.

FIGS. 101A-101D illustrates an implant 1242, such as a joint replacementcomponent, having a plurality of layers 1244 welded together to create acustomized implant. All the added layers 1244 may be made of polymericmaterial such as PEEK, PLLA, or polyethylene. Alternatively, some of thelayers may be made of a metallic or ceramic material (FIG. 101B). Thelayers may alternate between metallic/ceramic and polymeric material. Inaddition, the layers also may alternate between different polymeric orthermoplastic materials (FIG. 101C). Regardless of which material(polymer, metal, ceramic) each layer includes, the layers can be bondedto form a customized structure (see, e.g., FIG. 101D).

This structure is analogous to plywood where multiple layers of materialare bonded together to form one unit. Instead, in the present invention,the “plyweld” is made of biocompatible layers of material which arethermally bonded together either by spot welding or full surfacewelding. Plyweld may be especially useful for minimally invasive surgeryand nanotechnology applications where implants may be constructedintracorporeally to create a unitary structure. Such structures may beadvantageous for cell therapy, gene therapy, drug delivery, bearingsurface implants, and other suitable applications.

At least one of the layers of the plyweld structure may have an ingrowthsurface. For example, a joint replacement component may have a bearingsurface on one side and an ingrowth surface on the other side that, whenimplanted, is in contact with tissue. The ingrowth surface may beporous, honeycomb, biodegradable, biostable, or made from foam metal orfoam titanium. The ingrowth surface may include a therapeutic substance,such as tantalum, HA, apatite, BMP, or other suitable agent

In another embodiment of the present invention, joint replacementcomponents can be made with a hardened bearing surface film bonded to apolymer. PEEK may be combined with a metallic or ceramic film to createthe bearing surface. Joint replacement components generally employ metalon metal, such as cobalt chrome against cobalt chrome, or ceramic onceramic. In the present invention, one or more bearing surfaces of ajoint replacement component could be made out of PEEK which may have anano-metallic or nano-ceramic film bonded to its articulating surface.For example, a diamond crystal or aluminum crystal may be bonded to thePEEK. The polymer may be a few microns to as much as 100 microns inthickness. For minimally invasive surgery, this embodiment isadvantageous since the surgeon could introduce the implant bearingsurface of smaller components into the body through a small incision.The components may be introduced through a cannula, under endoscopicguidance, or under magnetic guidance. Once inserted, the components maybe welded together and attached to bone. It is contemplated thatintracorporeally welding applies to other types of implants as well,such as modular stents, modular spinal cages, modular acetabularcomponent, modular hone plates, modular IM rods, modular spacers, andmodular wedges.

In addition to visualizing modular components during implantation, thecomponents (joint replacement, spinal, intravascular) may bemagnetically guided into and within the body. Magnetic particles, suchas iron oxide or iron particles, may be placed within the polymericcomponents. A magnetometer or other known energy source may be used toidentify the location and orientation of the modular components to aidin attaching the components to each other and to tissue. The ironparticles may also enhance the thermal welding properties of thecomponents. As previously discussed, metallic particles disposed withinor on the surface of a thermoplastic material would aid in transferringenergy, such as vibratory or heat energy, thereby creating an enhancedbonded interface.

Whether welding different layers together to form a plyweld orultrasonically welding to other implants together, the bonding regionbetween two components may be enhanced with textured surface technologyto increase the frictional characteristics of the components. A textureon the surface, usually opposite the energy director, increases weldstrength, reduces flash and particulate matter, and reduces the totalamount of energy required to weld the components. The components mayinclude thermoplastic and/or metallic material. Two components made ofsimilar material may be welded together using textured surfaces, or twocomponents made from different materials may be bonded using texturedsurfaces. A microtextured surface may include small surface projections.For example, FIG. 102A shows an implant with pebbles 2246. In FIG. 102B,the implant includes a scratched or roughened surface 1248. FIG. 102Cshows an implant with a grit blasted surface 1250, while FIG. 102Dillustrates an implant with fiber-like materials 1252 disposed on thesurface.

Thermally weldable implants may additionally, or alternatively, includea macrotextured surface. FIGS. 103A-103F illustrate various embodimentsof macrotextured surfaces. In FIG. 103A, one implant includes V shapedprojections 1254 and the adjacent implant includes V-shaped grooves1256. FIG. 103B shows convex bulges 1258 and concave indentations 1260.FIG. 103C illustrates a generally square projection 1262 and a squarenotch 1264. In FIG. 103D, the upper implant includes two squareprojections 1266. The lower implant includes one square notch 1268 and aT-shaped notch 1270. The square projection 1266 thermally welded intothe T-shaped notch 1270 flows into the “T” to form a locking bondbetween the layers.

FIG. 103E illustrates a textured fastener. The cap 1272 may be made ofthermoplastic material. The anchor 1274 may be made of thermoplasticmaterial and/or metallic material. The anchor 1274 includes amacrotextured surface on the inside of the anchor bore. Duringultrasonic welding, thermoplastic material of the cap 1272 flows intothe grooves, notches or recesses of the macrotextured anchor. In FIG.103F, the anchor 1276 includes a macrotextured surface at its proximalend or proximal surface. In this configuration, thermoplastic materialof the cap lid 1278 flows into the notches, grooves, or recesses of themacrotextured anchor surface.

In a related invention, FIG. 104 illustrates a tibial tray 1280 forimplantation during knee replacement surgery. Typically, a tibial trayimplant is fastened to the proximal end of the tibia with metal screws.Use of metal screws usually creates stress risers and can limit tissueingrowth. Also, the tibial tray may subside slightly when secured withmetal fasteners. To alleviate these common problems, thermoplasticfasteners 1282 utilizing features of the present invention may be usedto implant tibial trays 1280. The tray of FIG. 104 includes a pluralityor channels 1284 configured for receiving a thermoplastic fastener 1282.Any fastener disclosed herein or incorporated herein may be used tofasten the tibial tray. The tray may be made of metal. Alternatively,the tray may include both metallic and thermoplastic material. Forexample, the main body of the tray 1280 may be made of metal while theregions around the channels may be made of thermoplastic materials. Inthis embodiment, a thermoplastic fastener 1282 may be ultrasonicallywelded to bone and be bonded with the thermoplastic material of thetibial tray.

FIG. 105 shows a tibial tray 1290 which is similar to the tray of FIG.104. However, the tray in this embodiment includes a stem 1292. The stem292 may be made of metal, thermoplastic, or a combination thereof. Thetibial tray 1290 is positioned on the proximal end of the tibia 1294with the stem 1292 disposed in the medullary canal. Thermoplasticfasteners 1296 secure the tray to the tibia. Additional thermoplasticfasteners 1298 may be used to fasten the stem 1292 to the tibia 1294.The fasteners may include a core as described in FIGS. 81 and 82,although other fastener embodiments described herein may also besuitable.

In FIG. 106, a tibial tray 1300 includes a shortened stem 1302. As seenin the figure, the tibia is fractured in several locations.Thermoplastic components may be used to reconstruct the proximal end ofthe tibia. Initially, an intramedullary rod (“IM rod”) 1304 may bepositioned in the intramedullary canal of the tibia. The IM rod may bemade of PEEK or other material suitable for welding to other components.Existing metallic IM rods require fasteners to be place through thecortical bone and into holes disposed in the rod. This configuration isprone to create stress risers. Therefore, using a weldable IM rod allowsa surgeon to implant the rod within the bone and use thermoplastic pinsor fasteners that can be welded to the rod. The pins may be placedanywhere along the length of the rod including the ends of the rodwithout the risk of creating stress risers. This PEEK rod and pincombination allows unicortical or bicortical fixation to lock the rodwithin the bone.

The tray 1300 is placed on the end of the tibia with the shortened stem1302 inserted into a notch in the IM rod 1304. The stem and rod may beultrasonically bonded together. Thermoplastic fasteners 1306, with orwithout cores, may be used to fasten the tray to the bone and fasten therod to the bone. Additional fasteners may be utilized to secure afragmented ligament to its proper position as well as to secure athermoplastic bone plate to the tibia.

In another embodiment of the invention, bone filler implants 1310 areshown in FIGS. 107 and 108. In FIG. 107, two bone voids exist at theproximal end of the tibia. To properly align and secure a tibialreplacement component, two bone filler implants 1310 are positioned inthe voids. The filler implants 1310 may be made of thermoplasticmaterial and/or metal. Fasteners of the present invention are used tosecure the tibial tray and bone filler implants to the tibia. Ultrasonicenergy may be used to bond the fasteners to the tray, filler implants,and bone and to bond the filler implants to the tray and stem. FIG. 35shows another example of bone filler implants. An acetabular componentand a filler implant are thermally bonded to each other and arc securedto bone with one or more thermoplastic fasteners.

With respect to bone filler implants 1310, foam metal or porous metalscan be used. In one embodiment, the ultrasonic energy system accordingto be present invention has been used to create a channel for thethermoplastic fastener. Although this can result in arcing due to theinteraction between the ultrasonic energy and metallic material, thearcing can be reduced or eliminated by adjusting the welding parameters.With the channel formed, the thermoplastic fastener can then be used tobond the bone filler implant to the other component. In anotherembodiment, no channel is created in the foam metal. Rather, theultrasonic energy alone is sufficient to drive the thermoplasticfastener and create the bond.

Referring now to FIGS. 109A and 109B, the present invention may be usedto repair an impact fracture. FIG. 109A shows a bone, specifically afemur, with multiple impact fractures. To repair these fractures, achannel 1312 may be drilled through the bone and into the impact region.Using appropriate instruments inserted through the channel 1312, theimpacted bone may be repositioned to its anatomically normal position.Then, using ultrasonic energy, flowable thermoplastic material 1314 isplaced in the void of the impact region. The thermoplastic material 1314bonds to the bone and provides structural support for the impact region.

In a related invention, an acetabular implant 1320 is shown in FIGS.110A and 110B. The implant 1320 is made of thermoplastic material, suchas PEEK or PLLA. A plurality of holes 1322 extends through the walls ofthe implant and is configured for receiving a thermoplastic fastener.With the application of ultrasonic energy and pressure, the acetabularimplant 1320 may be welded to bone, and the fasteners may be thermallybonded to the implant and bone.

In addition to using ultrasonic energy to flow thermoplastic material inthe body, ultrasonic energy may also be used to weld metals and to meltsolder intracorporeally. Other energy sources may be used as well, suchas laser and cool plasma. Using intracorporeal metal welding andsoldering, electrical and electronic components can be implanted andrepaired in the body. For example, batteries from a pacemaker or otherpump may be replaced; temperature, pH, or pressure sensors may beconnected or reconnected; microprocessor or computer chips may berepaired; and entire circuit board may be implanted and electricallyconnected. These implanted electrical components may be encapsulatedwith thermoplastic material to protect surrounding tissue from damage,heat, shock, etc. and block body fluid from reaching the components.FIG. 111A shows a patient with a pacemaker 1330. Pacemakers usually havea limited service life and require replacement after a certain period oftime. With the method and devices of the present invention, a pacemakercan be repaired or upgraded in situ. Electrical connections may bedetached and reattached using ultrasonic energy and solder. Adefibrillator made be implanted and connected to an existing pacemaker.In FIG. 111B, various electrical components 1332 may reside in animplant. These components include diodes, transistors, transformers,rectifiers, integrated circuits, resistors, capacitors, memory chips,etc. These components may be repaired or replaced intracorporeally andin situ.

Metal to metal welding may also be performed intracorporeally usingultrasound, laser, and/or cold plasma. In FIGS. 112A and 112B, twostents 1334 positioned in a vessel 1336 are welded together to form oneunitary stent 1338. Both stents 1334 are made of metal and are welded toeach other in situ. In FIGS. 113A and 113B, multiple stents 1340 may bewelded together to form a desired configuration either in the operatingroom or within the vessel. Where two vessels form a “T” or “Y”′ in thevasculature, a surgeon can thermally weld one stent 1340 to anotherstent 1340 in a “T” or “V” configuration. Also, a plurality of smallerstents may be built up within the body to form a larger stent. Thismethod of welding tubular structures using metallic welding may also beapplied to balloons and conduit/tubing for medication pumps, diabetesinsulin pumps, and pain pumps. Also, electrodes to an electricalstimulation unit may be welded to extend them or to seal them off.

In another example of metal to metal intracorporeal welding, a metalimplant may be bonded to a metallic bone filler implant. FIG. 114 showsa metallic acetabular component implant 1342 in bone. A metal fillerimplant 1344 is welded to the acetabular component 1342. Fasteners 1346disclosed herein may be used to further secure the component and fillerimplant to bone.

The intracorporeal welding system of the present invention also mayinclude shrinkable materials for use in surgery. Shrinkable materialsprovide a compressive force to tissue or implants when energy isapplied. For example, a fastener may be implanted to secure an implantor tissue. The application of heat to the polymeric material of fastenercauses the fastener to shorten or shrink thereby increasing the forceprovided by the fastener. The fastener may be positioned through twoportions of a fractured bone then heated to shrink. The bone portionsare compressed together for proper healing. In addition to fasteners, asuture, cerclage, wire, or cable may be made of shrinkable material. Acable may be placed through tissue or bone, positioned across a joint,or connected with an implant. When energy is applied to the cable, itshortens thereby creating a tension force and securing the object(s) towhich is attached. A shrinkable cable positioned adjacent to or across ajoint provides rigid and/or dynamic stabilization of the joint.

FIGS. 115A and 115B illustrate a thermally bendable suture. In FIG.115A, the suture is knotted 1352. Frequently, however, knots creep andthe suture loses tension. To solve this problem, ultrasonic energy maybe applied to the thermoplastic material of the knot 1352. FIG. 115Bshows the suture knot 1352 thermally bonded/melted to itself to preventcreep. In FIG. 116, the suture 1350 is reduced in length/diameter usingultrasonic energy. FIGS. 117A and 117B illustrate heat shrinkableimplant pouches 1354. Implants placed in a pouch 1354 are sealed within.Applying energy to the pouch shrinks it to firmly hold the implanttherein. Thermoplastic fasteners may be used to secure the pouch withinthe body.

In another related invention, tissue may be bonded to tissue usingthermoplastic material and ultrasonic energy. As shown in FIG. 118A,thermoplastic material, such as PEEK or PLLA may be positioned betweentwo pieces of tissue. In FIG. 118B, an ultrasonic end effector and anvil1360 is used to press the two pieces of tissue 1362 and thethermoplastic material 1364 together. The thermoplastic material 1364bonds the tissue 1362. This method may be performed intracorporeally orin the operating room outside the body. The thermoplastic material 1364may include a therapeutic agent such as proteins, cells, growth inducer,or similar substances. Other agents include antibiotics, hydroxyapatite,anti-inflammatory agents, steroids, antibiotics, analgesic agents,chemotherapeutic agents, bone morphogenetic protein (BMP), demineralizedbone matrix, collagen, growth factors, autogenetic bone marrow,progenitor cells, calcium sulfate, immo suppressants, fibrin,osteoinductive materials, apatite compositions, germicides, fetal cells,stem cells; enzymes, hormones, cell therapy substances, gene therapysubstances, bone growth inducing material, osteoinductive materials,apatite compositions with collagen, and demineralized bone powder. U.S.Provisional Patent Application No. 60/728,206 entitled “Drug ElutingImplant” discloses means for delivering therapeutic agents. Theabove-mentioned provisional application is incorporated by referenceherein in its entirety.

Referring to FIG. 119A, a composite fastener 1370 is illustrated. Thecomposite fastener 1370 includes a metallic core 1372 with helicalthreads 1374 disposed on the distal portion of the core. A thermoplasticsleeve 1376 is positioned about and secured to the middle portion of thecore. The composite fastener 1370 is shown in FIG. 119B implanted in abone 1378. Initially, an IM rod 1380 may be positioned within themedullary canal of the bone. A channel is then drilled through the boneand IM rod. The composite fastener 1370 is inserted in the channel suchthat the threads of the fastener engage the cortex of the bone and thesleeve of the fastener engages the IM rod. Ultrasonic energy may beapplied to the fastener to thermally bond the sleeve and IM rod. A boneplate may be positioned between the head of the fastener and the bone.

In many of the experiments, tests, and examples described below andelsewhere herein, ultrasound energy was used to weld thermoplasticmaterial. The bond between implantable components may also be a chemicalbond, covalent bond, ionic bond, or a bond using Vanderwall forces. Itis contemplated that any energy source provided herein may be utilized.

Experiments and Testing

Testing of PEEK welding was performed with ultrasonic energy from anultrasound generator and handpiece. The end effector that contacts thethermoplastic component was 0.180″ in diameter, though other sizes maybe used. During the welds, approximately 7-9 lbs of load was placed onthe handpiece, which was delivered to the cap of the component duringthe weld. Settings of current=170 and time=3 second was initially used.The time corresponds to tenths of a second, so the weld time was 0.3seconds. The current value is on a 0-255 scale.

The majority of samples welded had a seat cap (fastener)/design as shownin FIG. 120. Seat caps 1380 that were tested were made from Acrylic,Nylon, UHMWPE and PEEK. In most cases the “anchor” in which the seat capwas welded into was a hole in a small block of the same material.However, with the Nylon samples, the anchor actually was threaded into asawbone for welding and testing. To simulate “tissue” ⅛″ thick neoprenewas used as it could compress a little. To test the weld, a stainlesssteel wire or USP 5 suture was placed through the neoprene and force wasapplied to the wire to try and break the weld. FIG. 121 illustrates theapparatus used to test the welds.

The neoprene “tissue” stretched when tensioned and in some tests theneoprene failed prior to the cap and weld failing. In tests with Acrylicseats, the weld failed (rather than the neoprene “tissue” failing) ataround 30 lbs. With the Nylon seats, the samples typically failed atloads of 30 lbs. UHMWPE samples did not weld well and the welds wereeasy to break by hand. In five PEEK seat tests, there were no weldfailures, even at loads of 38 lbs where the “tissue” failed.

Referring to FIG. 122, a fastener 1382 includes an anchor 1384 and acap/post nail 1386. The fastener 1382 includes a thermoplastic materialsuch as PEEK. The anchor 1384 includes a bore configured to receive thepost 1388 of the nail. The anchor 1384 also includes helical threads1390 disposed on the outer surface thereon. Using the threads 1390,thermal welding, or both, the anchor 1384 is lockable within tissue. Thedistal portion of the post and the distal portion of the anchor includea tissue piercing point 1392. In FIG. 123, a piece of neoprene 1394 isused to simulate tissue. The neoprene is fastened between the cap 1396and the anchor 1384. The post 1388 is thermally welded into the anchorbore using ultrasonic energy or other energy source.

Another test fastener 1400 is shown in FIG. 124. The fastener includesan anchor 1402 and a cap 1404. A distal portion of the anchor 1402 isconfigured for placement in tissue. The anchor 1402 may be mechanicallylocked in the tissue, thermally welded in the tissue, or a combinationof both securing techniques. The anchor 1402 may have a pointed post1406 which pierces the tissue requiring repair. The disc shaped cap 1404is then placed over the anchor post 1408, and energy, such as resistiveheating or ultrasound, is emitted thereby staking the cap 1404 on thepost 1408. The tip of the post may be contoured to a flattenedconfiguration to reduce its profile. In FIG. 125, a strip of neoprene1410, representing soft tissue, is held by the fastener 1400 of FIG.124. During surgery, the distal portion of the fastener would beanchored in tissue. The cap 1404 is welded to the anchor post 1408, andthe post is deformed to a flat configuration.

Testing was performed on components fastened using resistive heat. Thesimple prototypes were made from Acrylic and looked like the componentin FIG. 120. The post was attached to the anchor and was 0.105″ indiameter. The outer diameter of the cap and anchor was 0.236″. For thistest, a thin foil heater was attached to a handpiece and a boarddesigned in-house. The board delivered a pulse width modulation signaland 10 watts of power. During a strength test the weld failed at about30 lbs.

FIGS. 126 through 134 illustrate test samples of PEEK components. FIG.126 shows PEEK fasteners 1412 that were ultrasonically welded to a PEEKrod placed inside the sawbone. The holes drilled through the sawbone andinto the rod were drilled at the same time, as would be done in surgery.The small blind hole in the rod provides a flat surface for the fastenertip to weld against.

FIGS. 127 and 128 are of another PEEK rod with two different types ofPEEK fasteners 1414 ultrasonically welded to the rod 1416. In FIG. 127,the fastener 1414 was designed to pass fully through the rod 1416. Inthis case, the fastener 1414 is stepped and welds to the rod at themating of the hole entrance and the angled fastener surface. In FIG.128, there is a blind hole and the tapered bottom of the fastener 1414is welded at the bottom of the drilled hole.

FIGS. 129-131 show a PEEK plate 1418 secured to a sawbone 1420 withthread-in PEEK fasteners 1422. The two fasteners 1422 were threaded intothe sawbone 1420 on opposite sides of a fracture 1424. The plate 1418was secured as a cap 1426 was welded to the first fastener 1422, thenthe other was welded. The plate 1418 had slots predrilled through it,but it is possible that it could be drilled in surgery at the same timeas the bone with the fastener passed through the newly drilled platehole, provided that the welded cap 1426 is larger in diameter than thenewly drilled hole.

FIG. 132 shows a small PEEK plate 1430 with fasteners 1432ultrasonically welded to the hole openings. FIGS. 133 and 134 show 30percent carbon reinforced PEEK fasteners 1434 welded to a rod 1436 ofthe same material.

In all of the cases, the welds were made with an ultrasonic handpieceand generator with a manual pressure applied by hand (in the 6 to 9 lb.range) with a weld time of 0.3 seconds. All of the welded specimens weretested by applying force with the hands. None of the welds failed. Whilethe test specimens shown in FIGS. 126-134 were all made of medical gradePEEK, it is contemplated that other materials such as Acrylic, PMMA,polypropylene, polycarbonate, acetal, and polyphenylsulfone (RADEL) mayalso be used.

Further testing was performed with test samples made from virgin PEEK(non medical grade). FIG. 135 shows the test fastener 1438 and anchor1440 used. The anchor 1440 in these samples was made so that it could besecured in a vise during welding and tensile testing. The samples wereultrasonically welded with an ultrasonic generator and handpiece. Theweld time was 0.3 seconds, and pressure of about 7-8 lbs. was applied tothe fastener by hand during welding.

FIG. 136 illustrates a fixture 1442 made for testing the samples. Thetop section mounts to the ultrasound generator and the bottom piece hasa small hole in 0.040″ thick aluminum so that the fastener post can passthrough it. Samples were welded with this plate between the fastener1444 and anchor 1446 sections as tissue would be. In the first set oftesting, pull force was applied to the fastener in the direction of thepost and anchor bore axis. The test was designed to preload the sampleto 0.5 lbs, and then apply further force at a loading rate of 1.25 mm/s.The results are provided in Table 1, below.

TABLE 1 Tension Load Testing Results Number of samples: 6 AverageFailure Load: 46.0 lbs Standard Deviation: 18.1 lbs Maximum FailureLoad: 75.5 lbs Minimum Failure Load: 20.3 lbs . . .

A second set of testing dealt with placing a shear load on the post in adirection perpendicular to the axis of the post and anchor bore. Thisload may be similar to what would be applied by tissue stretched over tobe repaired. The preload and loading conditions for this test areidentical to the prior test set. The orientation of the pull was theonly difference. The results are provided in Table 2, below.

TABLE 2 Shear Load Testing Number of samples: 5 Average Failure Load:76.6 lbs Standard Deviation: 10.5 lbs Maximum Failure Load: 91.7 lbsMinimum Failure Load: 62.9 lbs

In both tests, the PEEK prototypes had strength far exceeding thestrength of a knotted USP 2 suture, which would be expected to be about35 lbs.

Further results of PEEK and Acrylic testing are shown in FIGS. 137 and138. As seen in FIG. 137, the mean failure tension load for PEEKultrasonic weld samples was 46 lbs. while the mean failure shear loadwas about 76 lbs. In FIG. 138, the mean failure tension load for Acrylicheat stake samples was 29 lbs.

Exemplary Instruments

As previously discussed, a variety of energy emitting instruments may beused with the surgical welding system of the present invention. Theinstrument may produce energy such as resistive heating, radiofrequency,ultrasound (vibratory), microwave, laser, electromagnetic, electroshockwave therapy, plasma energy (hot or cold), and other suitableenergy. FIGS. 139-142 illustrate an exemplary instrument 1450 andfastener 1452 of the present invention. The instrument 1450 shown is anultrasonic handpiece with a sheath 1454 to cover and protect the endeffector 1456 and hold the fastener. The sheath 1454 has a small counterbore at its tip to cover a portion of the cap 1458. There is also abushing at a nodal point of the ultrasonic signal to prevent the endeffector 1456 from contacting the sheath 1454. The tip of the endeffector 1456 has a small post 1460 sticking out of the welding facewhich presses into a bore in the cap of the fastener. This can helpalign the fastener post into the anchor bore and keep the cap tightagainst the end effector face. After welding, the end effector 1456easily pulls off.

The post 1460 on the end effector 1456 could be threaded or have a Morsetaper to mate with the cap. Alternatively, the end effector 1456 mayhave a bore that the top of the cap mates into. The mating of thecomponents could also be by threads or a Morse taper along with astraight post. Furthermore, the pin could be roughened on the outsidesurface for better adhesion.

Another exemplary instrument is illustrated in FIGS. 143A and 143B. Asmall cartridge heater 1462 may be used to deliver thermal energy. Theheater 1462 may by a SUNROD ⅛ inch cartridge heater. To prevent heatbuild up of the outside shaft 1464, an air barrier may be formed betweenthe heater and the shaft. In FIG. 143A, four set screws 1466 are used tocreate an air barrier, while in FIG. 24B, a single set screw 1466 isused.

Referring to FIGS. 144A-144K, energy emitting instruments includevarious horn configurations. In FIG. 144A, the horn 1470 emits energy tothe top surface of the implant as well as the central core. The horn1472 of FIG. 144B is recessed to hold the thermoplastic implant 1474during welding. In FIG. 144C, the horn 1476 is concave to provide arounded surface to the implant 1478 after welding. The horn 1480 of FIG.144D is concave and includes a central extension 1482 to deliver energythroughout the implant 1484. In FIG. 144E, the horn 1486 includes aspike 1488 within disposable within an implant 1490. The horn 1492 ofFIG. 144F includes a threaded pin 1494 which is received by a bore inthe implant 1496. In FIG. 1440, the horn 1498 includes dual spikes 1500.The distal portion of the horn 1502 of FIG. 144H is dimensioned to fitwithin the thermoplastic implant 1504. In FIG. 144I, a sleeve 1506 isdisposed about the horn 1508 and implant 1510. The side-weld horn 1512is shown in FIG. 144J. In FIG. 144K, a dual horn welder 1514 is used tosimultaneously weld two fasteners 1516.

Exemplary Applications

The following examples further illustrate the diversity of the surgicalwelding system of the present invention. It is contemplated that theabove description regarding welding parameters, thermoplastic material,and instruments may be used with the following examples. This list ofexamples is not all inclusive but rather shows some specificapplications on how and where thermal welding may be utilized duringmanufacture and/or surgery.

FIGS. 145A and 145B illustrate one embodiment of the present invention.An anchor 1520, which may be made of PEEK or other suitable polymer, isplaced into a predrilled passageway 1522 in bone 1524. An end effector1526 is pressed against a surface of the anchor 1520 and ultrasonicenergy is emitted from the effector. The energy softens the polymerthereby deforming the polymer and driving the anchor 1520 into the boneand locking the anchor within the bone. No initial mechanical lock isrequired. However, as previously discussed, the application ofultrasonic energy may be in lieu of or in addition to a mechanicallocking means, such as threads.

In FIG. 146, a fractured bone has two sections 1530, 1532 which need tobe rejoined and compressed for proper healing. The anchor 1534 is lockedin the bone as previously described. A guidewire 1536 may be drilledfrom one bone section, through the fracture, into the other bonesection, and to the anchor 1534. A cannulated drill 1538 may be used tocreate a bigger hole over the guidewire. After the channel is created,the drill can be removed.

Next, as shown in FIG. 147, a fastener 1540, which includes a cap 1542and post 1544, is attached to the anchor 1534 to secure the tissue. Thefastener 1540 may be slid through the drilled hole, over the guidewire1536, across the fracture, and at least partially into the anchor. Thepost 1544 can then be welded into the anchor 1534 to close the fracturewith the cap 1542 placing pressure against the outer surface of the boneto apply compressive force to the fracture. Further energy may beapplied to the cap to deform or contour it to make it less obtrusivefrom the bone. Soft tissue and/or a bone plate may be positioned underthe cap of the fastener.

In FIG. 148 a guide instrument 1546 is shown. The instrument properlyaligns the drill and fastener 1540 into the anchor 1534. The instrument1546 may be an aiming or alignment guide or some type of triangulationdevice. The instrument 1546 may be adjustable to fit various sized ofbone/tissue or different angles of fastener insertion. FIG. 149 shows ananchor 1534 with multiple fasteners 1540 disposed therein.

In the embodiments described in FIGS. 145-149, the post 1544 of thefastener 1540 may be threaded. That is, when drilling the channelthrough the bone sections 1530, 1532 and across the fracture, the drillmay be extended into or through the anchor 1534. A tap may be used tocreate helical threads within the channel in the anchor. Then, thethreaded post of the fastener may be inserted in the channel and screwedinto the anchor to thereby close the fracture. Energy may be used tofurther lock the fastener to the anchor. Alternatively, the post 1544may extend completely through the anchor and extend out the oppositeside of the anchor. In this configuration, a threaded nut may be placedon the distal end of the post. Furthermore, the distal end of the postmay be thermally flattened or contoured. In another related embodiment,the cap 1542 of the fastener 1540 may be angled or may float or pivot onthe proximal end of the post. This could allow the cap to lay flushagainst the tissue surface.

FIGS. 150A and 150B illustrate another application of the surgicalwelding system. Ultrasonic energy may be used to bond a metal/ceramicimplant to a polymeric implant or a polymeric implant to anotherpolymeric implant. A polymer implant 1550 is positioned against ametallic implant 1552. An extension or spike 1554 may extend from thepolymer and be positioned through the metallic implant. Using ultrasonicenergy, the extension is excited and formed by an ultrasonic horn 1556or other energy source to soften and move over the metal therebysecuring the two implants to each other.

Referring to FIGS. 151A and 151B, ultrasound energy may be used to movea first, polymeric material 1560, such as PEEK, into a second material1562 that is more resistant to softening by an energy source. The secondmaterial 1562 may have a higher melting point, such as metal, ceramic,or a different thermoplastic material. Alternatively, the secondmaterial may be formed of a thermoset material. The polymer componentmay have energy directors that fit into a passage in the secondmaterial. The second material also may have undercuts or cavities 1564for the polymer to move into and fill. As the PEEK is excited by theultrasound energy, it moves into the voids of the second material. Afterthe energy is removed, the polymer cools to mechanically lock the twodissimilar material components together.

In a further embodiment of the present invention shown in FIGS. 152-155,the surgical welding system may be used to repair and/or stabilizejoints of the spine such as intervertebral joints and facet joints.Stabilization of the spine is usually achieved by attaching rigid rods1570, plates 1572, spacers 1574, or wedges 1576 between two or morevertebrae. Fasteners 1578, such as screws, are inserted into thevertebrae, and the plate 1572 and/or rod 1570 is mechanically connectedto the fastener 1578. The spinal rods, plates, fasteners, etc. mayinclude thermoplastic material of the present invention, such as PEEK orPEAK. The implants may be biodegradable or biostable. For example, thefastener 1578 may be made of metal, and the rod 1570 or plate 1572 maybe made of PEEK. The metal may be affixed to vertebrae, while polymericrods may be welded to the fastener using ultrasonic energy.Alternatively, the fasteners 1578 may be made or PEEK, and the rods maybe made of metal. The fasteners may be implanted in the vertebrae usingenergy, as previously disclosed. The rods/plates may be aligned withfasteners, and the polymeric material of the fasteners may be welded tothe rods. Furthermore, both the fasteners 1578 and rods 1570 or plates1572 may be made of PEEK. The fasteners are implanted in vertebrae bysoftening the PEEK with energy. The rods are attached to the fastenersalso with energy, such as ultrasonic energy.

The fasteners and rods/plates also may include both PEEK and metal. Forexample, the fasteners may have a distal portion made of PEEK whichthermally locks in bone by applying energy. The proximal portion of thefastener may include metal which may mechanically and/or thermally lockwith a rod or plate. Alternatively, the distal portion of the fasteneris metal, and the proximal portion is PEEK. Other embodiments of theinvention using a composite of materials may also be used. Likewise, therod and/or plate may also include both metal and thermoplastic material,such as PEEK. The rod and/or plate may be made mostly of metal; however,the plate may include PEEK where the fasteners attach to the rod/plate.It is contemplated that the fasteners, plates, and rods described hereinmay be made of PEEK, metal, ceramic, composite, or another polymericmaterial.

FIG. 155 shows a modular vertebral body replacement system 1580. Thethermoplastics and energy of the present invention may be used to bondthe components together intracorporeally. The CONSTRUX system in FIG.155 is designed to be mechanically locked together during surgery. Usingthermoplastics, the unit may be mechanically and thermally lockedtogether using welding processes described herein.

Additional exemplary fasteners are illustrated in FIGS. 156A-156F. Thefastener 1580 of FIG. 156A is made entirely of a thermoplastic materialsuch as PEEK. In FIG. 156B, the fastener 1582 includes two differentthermoplastic materials 1584, 1586. Each material may have differentwelding properties. FIG. 156C shows a fastener 1588 with only a proximalportion 1590 made of PEEK, while FIG. 156D illustrates a fastener 1594with only a distal portion 1598 made of PEEK. In FIG. 156E, the fastener1600 includes a rigid metallic core 1602 which is enclosed by athermoplastic 1602, such as PEEK. The fastener 1606 of FIG. 156F has apolymeric core 1608 surrounding by a thermoplastic 1610, such as PEEK.

Moreover, thermal energy used to soften and bond PEEK may also be usedto contour and deform the fasteners, plates, and rods. Energy, such asresistive heating, may be applied to the plates and rods to shape themto a desired and anatomical configuration. Also, the fasteners, rods,and plates may be deformed using energy and positioned such that thecombination produces compression or tension between two or morevertebrae.

In a further embodiment, the surgical welding system may be utilized toprovide flexible stabilization of the spine, or any other joint or boneof the body, as suggested in FIGS. 152-154. The soft tissue around andnear a joint may become weakened over time, and the range of motion ofthe joint usually increases thereby allowing excessive tissue laxity.Also, instability of a joint may be caused by structural changes withinthe joint as a result of trauma, degeneration, aging, disease, orsurgery. An unstable spinal joint may be rigidly stabilized aspreviously explained or may be dynamically stabilized to allow somerange of motion of the spinal joints. Fasteners, screws, plates, rods,etc. made of PEEK may be implanted between two or more vertebrae. Theplates and rods are configured and dimensioned to permit some flexingand/or bending. The amount of flexibility of these PEEK implants may beadjusted by the surgeon in the operating room using energy, such asultrasound, resistive heating, etc. and varying the weld parameters.

Additionally, as seen in FIG. 154, a plate 1572 or rod 1570 may beconfigured to lock with a fastener 1578 in one direction, but wouldallow movement in another direction. For example, the plate and fastenerpermits superior and inferior motion of the spine but would preventlateral motion. Also, the plate and fastener may permit motion in oneplane and restrict motion in a different plane. Other devices andmethods for dynamic stabilization of the spine and other joints andbones are disclosed in U.S. patent application Ser. No. 11/258,795entitled “Devices and Methods for Stabilizing Tissue and Implants” filedOct. 26, 2005. The contents of the aforementioned patent application areincorporated herein by reference in its entirety.

In another embodiment, the welding system of the present invention maybe used to thermally weld a spinal spacer or spinal cage to a bone.Currently, spinal cages are threaded into the spine or mechanicallylocked into the spine with bards, threads, etc. In the presentinvention, the spinal cage may be made of PEEK and could lock intotissue by the application of ultrasonic energy and/or by the use of PEEKfasteners. The fasteners may extend from the cage to adjacent vertebrae.The fasteners may function as tension or compression bands to hold thecage in place. Additionally energy, such as resistive heating, may beuse to contour the cage or spacer to a desired configuration such as toconform with the geometry of adjacent vertebrae. If multiple cagesand/or spacers are required, the implants may be thermally weldedtogether before implantation in the operating room, intracorporeally, orboth.

In yet another embodiment of the present invention, the surgical weldingsystem may be used to repair and stabilize a knee joint. For example, asseen in FIG. 157, a ligament (ACL), tendon, or bone graft 1612 may befastened into position using thermoplastics and energy. Other polymersmay be welded across the joint to provide rigid and/or dynamicstabilization. Also, a joint replacement component may be modified usingthermoplastics and energy. In FIG. 158, one or more stabilizers 1614 maybe bonded to the joint replacement component to provide stabilitybetween the tibial and femoral components 1616, 1618. It is contemplatedthat other joint replacement components, such as the hip, shoulder,elbow, ankle, etc. may include thermoplastic stabilizers. As seen inFIG. 158, the tray 1614 may be spot welded (or surface welded) to thetibial base component 1616.

Furthermore, PEEK fasteners and PEEK material may be used to stabilizeor tether disc replacement components or other implants such as anorgan, partial organ grafts, tissue graft material (autogenic,allogenic, xenogenic, or synthetic), collagen, a malleable implant likea sponge, mesh, bag/sac/pouch, collagen, or gelatin, or a rigid implantmade of metal, polymer, composite, or ceramic, breast implants,biodegradable plates, porcine or bovine patches, metallic fasteners,compliant bearing for medial compartment of the knee, nucleus pulposusprosthetic, stent, tissue graft, tissue scaffold, biodegradable collagenscaffold, and polymeric or other biocompatible scaffold. As illustratedin FIG. 159, fasteners 1620 may be attached to or placed around theimplant 1622 and secured to adjacent tissue preventing the implant frommigrating. Other methods of tethering implants are disclosed in U.S.patent application Ser. No. 11/258,795, previously mentioned andincorporated by reference herein.

In another spinal application, a spinal implant may include athermoplastic material to which a bearing surface coating may beapplied. A nano-ceramic coating may be bonded to a spacer which is usedto change positions of bones of a joint. The coating may be 3-5 micronsthick or could be as thick as 50 microns. The coating may be alumina,Zirconia, or diamond type ceramic which is welded to the spacer usingultrasound energy, resistive heating, or other energy source. The spacermay be stabilized or tethered using PEEK fasteners as previouslydescribed. In one embodiment, the spacer is affixed to one vertebra withfasteners, and the other side of the spacer which includes the bearingsurface coating is free to articulate against the adjacent vertebra. Inaddition to PEEK, other polymers such as polyurethane, polyethylene,polyester, or DELRIN may be used.

It is also contemplated that the welding system of the present inventionmay be used with other surgical applications. For example, cerclage wiremay be made of PEEK. The wire could be used to secure a cervical platefor unicortical or bicortical fixation. Energy may be used to weld thewire and plate together. Energy may also be used to change the angle offixation and to contour the plate. PEEK implants may be used tostabilize nucleus pulposus replacement components or to repair theannulus. PEEK implants may be used in a kyphoplasty. A balloon or meshmay be inserted into a spinal void. The mesh may be filled with fluid orgraft material to expand the adjacent vertebral bodies. The mesh sackmay then be scaled and anchored into position to prevent migration. Themesh, graft material, seal, and/or anchor may be made of PEEK and may bebiodegradable material.

In a further application of the invention, the surgical welding systemmay be used with for intracranial and craniofacial surgery.Thermoplastic implants may be used to stabilize craniofacial plates. Theplates may be contoured with energy to obtain the desired shape. PEEKfasteners may be implanted in tissue via mechanically, thermal welding,or both, and the plate may be attached to the fasteners via mechanicalmeans, thermal welding, or a combination thereof. For face lifts, one ormore PEEK fasteners and a suture or cable may be used to create a slingto reposition and tighten soft tissue such as skin. The fasteners may besecured to bone or other tissue. The suture may be positioned throughthe soft tissue using a magnetic suture passer and magnetic guidancethereby achieving a minimally invasive facial support. The fastenersand/or suture may be secured unicortically to the skull, mandible,maxilla, or other bones of the head. Also, PEEK may be used for sealingcerebrospinal fluid leaks. This may be performed with a thermoplasticand energy source, with or without vacuum/suction.

In another embodiment of the present invention, a fastener includesmultiple portions made from a different polymeric material. For example,the fastener may have dual dermometry properties. (see, e.g., FIGS.156A-156F). For instance, the cap may be made of one polymer while thepost may be made of a different polymer. The two polymers may havedifferent temperature transition regions. Therefore, one polymer wouldsoften before the other polymer. Also, if using ultrasonic energy, thetwo polymers may soften at different frequencies, wattages, pressures,or other welding parameters. Alternatively, the post may be made of apolymer that softens with ultrasound, while the cap may be made of apolymer that softens with resistive heating. It is contemplated that anyof the implants and devices disclosed herein may include multiplepolymers having different welding parameters.

In addition to PEEK and the other polymers described herein, theimplants, devices, and methods of the present invention may use keratin,a naturally occurring polymer. Keratin may be ultrasonically welded toitself: to other implants, or within tissue. This may be performed inthe operating room or intracorporeally. Keratin may be bonded tocollagen or to other known polymers. In an exemplary application,keratin may be used to fasten tissue to bone since keratin has BMP andtissue scaffold properties. It is contemplated that any of devices andmethods disclosed herein may utilize keratin alone or in combinationwith PEEK, polylactic acid, or other polymer. Keratin may be used tomake fasteners, disc replacements, joint replacement components, stents,cell scaffolds, drug reservoirs, etc. Also, joint bearing surfaces mayinclude keratin with or without collagen or chondrocytes. The bearingsurfaces may be fastened to a joint component using PEEK or PLAfasteners.

The surgical welding system also includes shrinkable materials for usein surgery. Shrinkable materials provide a compressive force to tissueor implants when energy is applied. For example, a fastener may beimplanted to secure an implant or tissue. The application of heat to thepolymeric material of fastener causes the fastener to shorten or shrinkthereby enhancing the force provided by the fastener. The fastener maybe positioned through two portions of a fractured bone then heated toshrink. The bone portions are compressed together for proper healing. Inaddition to fasteners, a suture, cerclage, wire, or cable may be made ofshrinkable material. Cable may be placed through tissue or bone,positioned across a joint, or connected with an implant. When energy isapplied to the cable, it shortens thereby creating a tension force andsecuring the object(s) to which is attached. A shrinkable cablepositioned adjacent to or across a joint may provide rigid and/ordynamic stabilization of the joint. FIGS. 160A-160C illustrateconfigurations and uses of heat shrinkable implant pouches 1624.Implants 1626 may placed in a pouch are sealed within. Applying energyto the pouch 1624 shrinks it to firmly hold the implant 1626 therein.Thermoplastic fasteners may be used to secure the pouch within the body.

In a further embodiment of the present invention, thermoplastics andenergy may be used to repair a hip joint. As shown in FIG. 161, bearingsurface implants 1628 may be bonded to the acetabulum. Fasteners 1630may also be used to secure the implants 1628. In FIG. 162, a prostheticfemoral head 1632 is attached to the femur with a fastener 1634. Thehead includes a thermoplastic material 1636 bonded to the surface tofunction as a bearing surface. The thermoplastic 1636 may articulateagainst acetabulum implants. FIG. 163 shows PEEK 1638 disposed on thesurface of the femoral head. A bearing surface material 1640, such asnano-metal or nano-ceramic is welded to the PEEK. On the acetabulum, abearing surface material is also welded to the bone with PEEK. With thereplacement components implanted, the bearing surfaces articulateagainst each other.

As previously discussed, the anchor bore may be configured to receive atool, such as an allen-type wrench, a screwdriver, or the like so thatthe anchor can be rotated into or out of the bone, tissue, or implant inwhich it is placed. The fastener cap may then be disposed in the anchorbore for fastening another bone, tissue, or implant material to thefastener assembly. FIGS. 164-169 further illustrate this aspect of theinvention. As shown in FIG. 164, for example, the anchor 1650 has a boreconfigured for receiving an allen-type wrench. The figures illustrate ananchor bore that is square-shaped with rounded corners, although otherallen-wrench shapes such as hexagonal shaped, star-shaped, pentagonalshaped, or the like may likewise be suitable to allow torque to beimparted to the anchor in order to help drive the anchor into bone,tissue, or implant material.

External threads 1654 engage with the bone, tissue, or implant materialso that rotation of the anchor in one direction causes it to be drivenfurther into the bone, tissue or implant material, while rotation in theopposite direction causes the anchor to be removed. Once the anchor isdeployed into the bone, tissue, or implant material, the alien-typewrench may be removed from the bore and a fastener cap 1656 may beinserted into the bore and held in place at least in part by welding aportion of the cap 1656 to a portion of the anchor. As previouslydiscussed, the fastener cap 1565 and/or anchor 1652 may be configured toresist relative movement of the cap and anchor prior to welding or morepermanent connection of the fastener cap to the anchor.

To further illustrate this embodiment of the invention, FIG. 165 depictsthe fastener cap post 168 having a cross-sectional shape correspondingto the shape of the anchor bore 1652. One potential advantage of thisembodiment of the invention is that it may allow the physician to applya greater amount of torsional force to turn the anchor further into orout of the bone, tissue or implant material even after the anchor andcap have been welded together. That is, the allen-type configuration ofthe anchor bore and fastener cap post may allow the assembly towithstand greater amounts of torsional force without damaging the weldthan may be achieved with an anchor bore and fastener post havingcorresponding circular cross-sections.

As mentioned previously, an anchor bore configured to receive anallen-type wrench, screwdriver, or the like may have different shapesthan merely what is illustrated in FIGS. 164-168. Likewise, a fastenercap having a cross-section corresponding to the anchor bore may be usedas an allen-type wrench to position the anchor. Thus, the cap 1656 mayinserted into the anchor 1652 and then rotated until the anchor isdeployed in a desired position. Rotation of the fastener cap can beachieved in several different ways. For example, an open-ended wrenchmay be used to grip the cap post 1658 and turned in a clockwise orcounter-clockwise direction. Similarly, the cap lid 1660 may beconfigured to receive a wrench that allows the fastener assembly to berotated in or out of position. As shown in FIGS. 165-168, for instance,the cap lid 1660 may be hexagonal shaped to receive an open-ended orclosed wrench that allows the fastener cap 1656 to be rotated and imparttorsional forces on the anchor.

FIG. 165 shows that a welding bore or recess 1662 may be provided thatallows a welding device to be aligned with and impart energy to theanchor. The welding bore also may be configured to receive a tool eitherbefore or after welding, or both, that allows a physician to manipulatethe fastener. For instance, a fastener that has been already secured toan anchor may receive a tool for rotating the assembly either furtherinto or out of its position in the body. Thus, the shape of the weldingbore or recess 1662 may be configured to receive an allen-type wrench, ascrewdriver, or the like so that torsional forces may be exerted on thefastener.

Similarly, and as shown in FIGS. 164-168, the fastener lid 1660 maylikewise be configured to receive a tool that allows a physician tomanipulate the fastener or fastener assembly. For instance, the fastenerlid 1660 may be configured to receive a clamp or wrench that allows aphysician to impart forces on the fastener assembly or componentsthereof

Providing features in the fastener that allow a physician to manipulatethe assembly may be useful in several different ways. For instance, sucha configuration may allow a physician to weld the assembly together andthen rotate it to further deploy the assembly into the body. Such aconfiguration also may facilitate easier removal of the assembly at alater time. This configuration also may permit a physician to make oneor more adjustments in the deployment or positioning of the fastenerassembly, either during the initial procedure or later in time. Whilesuch benefits each have advantages, it should be noted that noembodiment of the invention requires these advantages to be realized inorder to fall within the scope of the invention.

Welding of the tack to an inside bore of an anchor may result in acollapse of the tack during the weld. As a result of this collapse, thegap distance between the anchor top surface and the underside surface ofthe tack may decrease. This reduction in the gap may be beneficial forfurther ensuring that the material disposed in the gap is more securelyheld in place by the fastener assembly. For instance, the weldingprocess may cause the gap to be reduced 1 mm or more due to welding.This reduction may therefore cause the cap lid and top of the anchor toimpinge on the tissue or implant materials disposed in between thesesurfaces.

In some instances, it may be desirable to fine-tune the security of thetissue and compression against the bone. As mentioned above, thefastener may be configured to receive a tool that allows manipulation ofthe assembly. In this manner, the fastener lid 1660 may be manipulatedto drive the anchor 1650 and cap 1658 further into the bone. This woulddecrease the distance between the cap lid 1660 and bone, better securinga thinner tissue or implant material disposed therebetween by placing itunder more compression. Alternatively, if it was thought that tissue wasunder too much compression the fastener cap could be turned the oppositedirection increasing the gap between the bone and fastener lid. Aspreviously discussed, a washer may be disposed between the lower surfaceof the cap lid 1660 and the tissue or implant material that is beingfastened in place. As the cap lid is rotated or otherwise manipulated,the washer may help reduce damage to the tissue or implant material fromshearing forces that may be imparted from rotation of the cap lid 1660.

In instances where fine tuning is desired, the anchor bore 1652 and cappost 1658 may be configured to have corresponding shapes that allowtorsional forces to be imparted from the cap 1656 to the anchor 1650. Itshould be noted, however, that use of an anchor having a circular boreand a cap having a post having a similar circular cross-section maynevertheless allow manipulation of the assembly if the weld issufficiently strong. Nevertheless, configuring the anchor bore toreceive a tool, such as an allen-type wrench (e.g., a hex, star-shape,or other non-circular shape) and likewise configuring the cap post tohave a corresponding shape may allow greater torsional forces to beimparted on the assembly.

Additionally, such a configuration may allow the anchor placement to beadjusted even before welding takes place. For example, the anchor may beplaced in a first position. Implant material or tissue may be disposedbetween the anchor and a fastener. A portion of the fastener may beinserted through the implant material or tissue and into the anchorbore. If the physician then determines that the anchor position needsadjustment, the cap may be rotated to move it further into or out of thematerial in which it is placed. Once the anchor is in a desiredposition, the cap may be welded or otherwise secured to the anchor. Asnoted above, further adjustments in position of the assembly may be madeeven after the assembly is secured together.

FIGS. 164 and 165 also illustrate that the threads on the anchor mayfollow down a conical tip of the anchor. The placement of threads on aconical tip may allow the anchor to be more easily driven into bone at adesired location and angle.

As noted previously several embodiments of the invention may beconfigured such that the tip of the fastener is welded to the anchor.During welding, for example, a conical tip of the cap 1656 may bedisposed inside the anchor bore 1652 so that the conical tip contacts aninterior surface of the anchor. The cap lid may then be contacted by anultrasonic horn, which imparts energy to the assembly and causes weldingto take place inside the bore. The use of conical tip on the cap 1656also may allow the cap to more easily penetrate through the tissue orimplant material to be fastened.

FIGS. 172-174 illustrate an embodiment of the invention that helpssecure tissue to bone, such as in a humeral head model. A rod 1670 maybe disposed at least partially in a cavity in the bone. In someinstances, the rod may be threaded to help insert it into the cavity orto help it maintain a certain position. Alternatively, as shown in FIG.172, the rod may not have a threaded surface.

The rod may be disposed in an open cavity in the humeral head to bestabilized, extending through two bone cortexes. If only held on onecortex the rod may wobble. Fastener caps 1672 are then inserted into thebone, possibly by inserting them into pre-drilled holes or openings thatlead the fastener to the rod 1670. The fastener caps may be configuredto have a range of motion and rotation to allow the caps to move andadjust to the outer surface of the bone or tissue in which the fasteneris placed. Thus, if a fastener is inserted at an angle that is notperpendicular to the outer surface of the tissue or bone near thelocation of insertion, a moveable fastener head would adjust itsorientation relative to the cap post and provide greater contact withthe bone or tissue.

In one embodiment, the tips of the fastener caps contact the rod and thefasteners are exposed to an energy source that welds the fastener capsto the rods. Achieving good contact between the tips of the fastenercaps and the rod can be difficult, however, and the joint formed betweenthe fastener cap and the rod at the weld location may not remain secureover time. Additionally, the length of the cap post 1676 may not alwaysbe sufficiently long enough to contact the rod 1670.

Thus, in some embodiments of the invention, the fastener caps may beoriented to apply a biasing force to the rod, or to contact the rod atan off-axis location prior to welding. FIGS. 175-179 illustrateexemplary embodiments of different configurations and orientations ofthe fastener cap relative to the rod.

FIG. 175, for instance, is an exemplary embodiment where the tip 1680 ofthe fastener post 1682 is configured to have two or more contactlocations between the fastener and the rod. These multiple contacts areachieved in this embodiment by providing a notched tip 1680 of thefastener post 1682. Other configurations, such as curved or multi angledsurfaces at the fastener tip likewise may allow a fastener tip toestablish two or more contact areas, or alternatively a largercontiguous area of contact, with the rod 1684. When exposed to an energysource, the fastener tip 1680 may then be welded to the contacted areaof the rod 1684. The tip of the fastener post illustrated in FIG. 175can be used to apply a force against the rod to urge it against theopposite cavity wall from where the fastener is inserted. Once the rodis in a desired position, the fastener may be welded to the rod to holdit in place.

As stated previously, there may be times when it is difficult toestablish sufficient contact between the fastener tip or fastener postand the rod due to variations that may occur in the location of theassembly and extent of damage. FIGS. 176-179 illustrate severalexemplary embodiments where the fastener post exerts a biasing forceagainst the rod. FIG. 176, for example, illustrates a fastener 1690inserted into a cavity 1692 in the bone where a rod 1694 has beenplaced. A side portion of the fastener post 1696 is in contact with therod 1694, and preferably imparts a biasing force between the post 1696and rod 1694. The side of the post is then welded to the rod.

In these embodiments, a rod 1694 may be placed at least partially in acavity 1692 in a bone. One or more fasteners 1698 may then be positionedtoward the cavity 1692 at an angle that is offset from the longitudinalaxis of the rod. The leading edge of the fastener 1698 may be configuredto help urge the fastener through the bone, such as by having a pointedtip or perhaps by having helical threads that may drive the fastenerthrough bone when rotated.

Alternatively, a passageway may be drilled for the fastener so that itmay be more easily inserted. As the fastener post 1696 progressesfurther into the cavity 1692, it may contact the outer surface of therod 1694 at a position offset from the rod's axis. Further progressionof the fastener post 1696 into the cavity 1692 causes the rod 1694 andpost 1696 to exert biasing forces against each other. The rod maytherefore be moved toward cavity wall and held in place between the walland fastener post by the biasing forces imparted. Likewise, the fastenerpost 1696 may be designed to flex or bend so that it can exert a biasingforce against the rod while minimizing the risk of exerting too muchbiasing force on, or creating too much interference with a rod thatalready is impinged in the cavity.

FIG. 177 illustrates that multiple fasteners 1698 may be applied to therod 1694 at an offset position. Thus, the physician is able to selectmultiple locations for inserting fasteners 1698 and still have theability to secure the rod 1694 in a desired location. These embodimentsallow the use of a smaller diameter rod for insertion into the cavity1692, which may allow the rod to be inserted into position more easily.Once a fastener has been placed in a position where it is applying adesired biasing force, it may be welded to the rod. The biasing forceexerted between the rod and the side of the fastener post may improvethe strength or quality of the weld between the two components.Alternatively, one or more of the fasteners, and potentially all ofthem, may not be welded to the rod, but instead may be welded to thebone around the cavity.

FIGS. 178 and 179 illustrate an embodiment where a fastener 1698 havingmore than one fastener post 1696 may be used to help secure a rod inplace. In this embodiment, the fastener 1698 has a band 1700 connectingtwo or more fastener posts. The band may be pre-configured to fit adesired shape, or alternatively may be flexible so as to conform to theouter surface of the bone, tissue, or implant material on which it isplaced. In use, the fasteners are deployed into position and impartbiasing forces on the rod in the cavity. As the fasteners are deployedinto place, the band 1700 may contact the outer surface of the bone,tissue or implant material. The use of a band 1700 may help providegreater certainty in the angle or positioning of fastener posts 1696,may help exert a compressive force on the exterior or the bone, or mayfacilitate more efficient installation of fastener posts.

FIGS. 180 to 182 illustrate additional features of fasteners 1702 thatmay be used to help facilitate better welding between a rod and the sideof a fastener post 1704. In these embodiments, the fastener post 1704may not have a symmetrical cross-section. Instead, the fastener post mayhave an edge or projection 1706 extending outward from at least aportion of the fastener post 1704. The extending edge or projection 1706may be oriented to contact the rod and facilitate the creation of ashear joint weld with the rod. One possible benefit of the use of anextending edge is that it may allow for extra material that forms theedge to be welded while preserving more material of the fastener post.

Additionally, as illustrated in FIGS. 183 and 184, the rod may likewisebe prepared for receiving a shear or side weld. This may be achieved,for example, providing for a similar extending edge on the rod asdescribed above for fastener posts, or by surface treating the rod in amanner that encourages welding to take place. In addition, the rod maybe notched in advance of surgery or during the procedure. The notches1710 could be configured to receive a portion of the fastener post. Onepotential benefit of notching the rod 1708 may be that the area ofcontact between the rod and fastener may be increased. As notedelsewhere, however, no embodiment requires that any or all of thepotential benefits described herein be achieved in order to fall withinthe scope of the invention.

Several features of the invention also may be used to associate a rigidstructure, such as a plate, to bone or other tissue. FIGS. 185-190illustrate how some of these features may be used in this manner. First,one or more, more preferably two or more, anchors 1712 are positionedinto the bone, tissue, or implant material at a location where a plate1716 is to be placed. The placement of the anchors 1712 may beaccomplished in any manner described herein for other embodiments, andmay include one or more of pre-drilling the bone, tissue, or implantmaterial, configuring the anchors with threads 1714, expanding theanchor to create an interference fit, welding the anchor to the bone,tissue or implant material, or the like. Once the anchors 1712 are inposition in the bone, tissue or implant material, the ends of theanchors 1712 extending outward are placed into receptacles 1718 formedon the plate 1716. The receptacles 1718 may be used to help guide oralign the placement of the plate 1716 with the anchors 1712. As shown inthe figures, the ends of the anchors that are associated with thereceptacles may be shaped to facilitate welding of the anchors 1712 tothe plate 1716, and may include energy directors. Furthermore, the platemay be configured with receptacles 1720 for an ultrasonic horn or an endeffector of an energy source at a location near the receptacles on theopposite side of the plate from the receptacles. Applying the energysource at the receptacles 1720 causes the anchors 1712 to be welded tothe plate 1716.

As previously discussed with respect to the embodiment shown in FIG.175, the tip of a component may have a plurality of prongs. In theembodiments shown in FIGS. 191 and 192, multiple prongs 1730 are shownfor an anchor 1732. The prongs 1720 may be used to help place the anchorinto a bone, tissue, or implant material. FIG. 191 further illustratesthat one or more of the prongs may extend further than another prong.This configuration may be useful for piercing a curved surface or mayhelp make insertion of the anchor easier. Turning to FIG. 192, once theanchor 1732 has been inserted into place, a fastener 1734 may beinserted through an internal bore or cavity in the anchor. The fastener1734 illustrated in FIG. 192 resembles a nail, however other fastenerconfigurations described herein may also be used. The material of theanchor 1732 and fastener 1734 may be dissimilar to each other. Forinstance, a portion of the fastener, such as the head 1736 or post 1738,or both, may be made of a porous metal while the anchor may be made of aweldable material. Likewise, the fastener may be formed from weldablematerials while the anchor is made of a second, dissimilar material. Asdescribed elsewhere, the components of the fastener also may be made ofsimilar materials that may be welded together.

Insertion of the fastener 1734 into the anchor may cause the anchorwalls to be pushed outward and create an interference fit with the bone,tissue or implant material. FIGS. 193 and 194 illustrate this possiblefeature. Insertion of the fastener may cause a portion of the anchor toextend further into the bone, tissue, or implant material. Onceexpanded, the anchor may become more difficult to inadvertently loosenfrom its position. The fastener and anchor may be welded together tofurther ensure that the components do not become disassembledinadvertently and cause the fastener assembly to come loose prematurely.

There may be some instances where it is unclear how long a fastenerassembly or one of its components should be. For instance, the use offasteners with a rod in a cavity may result in the need for varyinglength components. FIGS. 195 and 196 illustrate that the location ofinsertion of a fastener along the length of a bone may result in theneed for longer or shorter components. One way to address this potentialneed for varying length fasteners may be to make multiple sizedfasteners. These varied length or sized fasteners may be provided in akit or assembled during or prior to surgery as needed.

A potentially simpler alternative, however, may be to provide trimmablefasteners that can be shaped to size by exposure to an energy source.When used with a rod, for example, one or more fasteners having a lengthgreater than needed to extend into the bone, tissue or implant materialand contact a portion of the fastener to the rod may be selected andinserted into the bone, tissue, or implant material. After the leadingportion of the fastener extending into the bone, tissue or implantmaterial reaches a desired position, a portion of the fastener mayremain extending beyond the outer surface of the bone, tissue or implantmaterial.

The extending portion of the fastener may then be exposed to an energysource as described herein for welding so that it can be removed and/orreshaped to conform more to the outer surface of the bone, tissue, orimplant material. Trimming of the extended portion of the fastener, iftrimming is to occur, may also be accomplished in part or in whole bymechanical operations such as cutting, abrading, crimping, or the like.As previously described, an energy source may be used to shape anyremaining material extending beyond the implanted surface. Thisembodiment may provide greater ability to customize the length of one ormore fasteners to be more suited for the location of deployment.

Although the present invention includes fastener concepts that eliminatethe need for sutures (so-called “sutureless fixation”). The presentinvention also includes fastener concepts that use suture, but withoutthe need for knots (so-called “knotless fixation”). For example, thefastener of FIG. 59 is a knotless fixation system. FIGS. 197 and 198show another knotless fixation system 1750. System 1750 includes ananchor 1752 that is similar to the anchor of FIGS. 164-171 and afastener cap or tack 1754 that is similar to the fastener cap of FIGS.164-171. In this regard, anchor 1752 is shown as a simple dowel with asubstantially smooth outer surface, but can be threaded or otherwiseprovided with protrusions or other surface features for engaging thetissue into which it is inserted.

Anchor bore 1756 is configured and dimensioned to receive shaft 1758 oftack 1754. Bore 1756 can be substantially cylindrical or can beconfigured for receiving an allen-type wrench. The figures illustrate ananchor bore that is square-shaped with rounded corners, although otherallen-wrench shapes such as hexagonal shaped, star-shaped, pentagonalshaped, or the like may likewise be suitable to allow torque to beimparted to the anchor in order to help drive the anchor into bone,tissue, or implant material. An anchor channel 1760 extends throughanchor 1752 and a tack channel 1762 extends through tack 1754 such thatone or more sutures 1764 can extend through both anchor 1752 and tack1754. When tack 1754 is partially inserted in anchor 1752, suture 1764can freely move since anchor channel 1760 is aligned with tack channel1762. However, as tack 1754 is further inserted in anchor 1752, channels1760 and 1762 misalign, trapping suture 1764. When the welding of anchor1752 and 1754 occurs, knotless fixation of suture 1764 is achieved.Experimental studies have shown that with anchor 1752 and tack 1754 madeof PEEK and suture 1764 made of polyethylene, knotless fixation can beachieved without any melting or degradation of the suture material.

As discussed in connection with other embodiments, tack shaft 1758 mayhave a cross-sectional shape corresponding to the shape of the anchorbore 1756. One potential advantage of this embodiment of the inventionis that it may allow the physician to apply a greater amount oftorsional force to turn the anchor further into or out of the bone,tissue or implant material either before or after the anchor and tackhave been welded together. This would allow depth control of insertionand/or further control of the suture tension. Rotation of the tack canbe achieved in several different ways. For example, an open-ended wrenchmay be used to grip the tack shaft and turned in a clockwise orcounter-clockwise direction. Similarly, the tack lid 1766 may beconfigured to receive a wrench that allows the fastener assembly to berotated in or out of position. Tack lid 1766 may include a weldingrecess 1768 that allows a welding device to be aligned with and impartenergy to the anchor. The welding recess also may be configured toreceive a tool either before or after welding, or both, that allows aphysician to manipulate the fastener. Thus, the shape of the weldingrecess may be configured to receive an allen-type wrench, a screwdriver,or the like so that torsional forces may be exerted on the fastener.

As set forth in other embodiments, the present invention contemplates awide variety of geometries or configurations for ultrasonic horns or endeffectors. FIGS. 199A and 199B illustrate curved end effectors.Ultrasonic horn 1770 mates with end effector 1772 in any number of knownmanner. The end of end effector 1774 couples with fastener 1774. Acurved end effector 1774, allows the fastener to get around curvedspaces inside the body. The curve could be a gentle curve, could be agradual curve or a small curve at the end of the end effector.

In one embodiment, the end effectors have a fixed curvature. As theconnection between the end effector and ultrasonic horn can be modular,this fixed curvature can be selected to be best suited for a particularclinical application. In another embodiment, the end effector isflexible so that the end effector can bend or otherwise conform to ashape needed for proper delivery and placement of the fastener.

A flexible member suitable for use as an end effector can be made indifferent ways. For example, a central portion of at least one componentof the flexible member may be hollow, resembling a hollow tube. One ormore slits may then be cut into the hollow tube. For instance, a tubemay have a helical spiral slit cut along at least a portion of the tube.Alternatively, the tube may have a plurality of diagonal slits cut intoits surface. The slits may be machined into the tube, such as by turningthe tube on a lathe, by milling the slits, using a wire EDM, or by othersuitable methods. The tube may also be formed from winding one or moreflat strips of material. The slits may be continuous along the entirelength of the flexible element or may be formed on only a portion of theflexible element, such as at the center or on one side.

Without being bound by any particular theory, it is generally thoughtthat the surgical welding system of the present invention causesprimarily radial deformation of the fastener. This was discussed abovein the context of collapse. Because the primary deformation is collapseso that radial expansion occurs, there is little, if any, elongation inthe longitudinal direction. This is shown schematically in FIGS. 200Aand 200B. Detailed analysis has shown that for a fastener or tack likethe one shown in FIG. 166 made of PEEK and having typical dimensions(head 0.180 inch; and tip 0.109 inch), there is a weld collapse of 0.050inch for set weld parameters (111 watts; 500 millisec weld time; and 5-8lbs force applied). As previously discussed, this collapse can beincreased or decreased by changing the weld parameters, the geometry ofthe end effector and tack, and/or material of the fastener.

It is contemplated the surgical welding system of the present inventionmay be used with and integrated with the methods and devices disclosedin U.S. Provisional Application No. 60/765,857 entitled “SurgicalFixation Device” filed on Feb. 7, 2006. In the '857 document, variousthermoplastic fixation devices are disclosed. The fixation devices maybe, but are not limited to, degradable, biodegradable, bioerodible,bioabsorbable, mechanically expandable, hydrophilic, bendable,deformable, malleable, riveting, threaded, toggling, barded, bubbled,laminated, coated, blocking, pneumatic, one-piece, multi-component,solid, hollow, polygon-shaped, pointed, self-introducing, andcombinations thereof Also, the devices may include, but are not limitedto, metallic material, polymeric material, ceramic material, compositematerial, body tissue, synthetic tissue, hydrophilic material,expandable material, compressible material, heat bondable material, andcombinations thereof.

The methods and devices disclosed in the '857 document may be used inconjunction with any surgical procedure of the body. The fastening andrepair of tissue or an implant may be performed in connection withsurgery of a joint, bone, muscle, ligament, tendon, cartilage, capsule,organ, skin, nerve, vessel, or other body parts. For example, tissue maybe repaired during intervertebral disc surgery, knee surgery, hipsurgery, organ transplant surgery, bariatric surgery, spinal surgery,anterior cruciate ligament (ACL) surgery, tendon-ligament surgery,rotator cuff surgery, capsule repair surgery, fractured bone surgery,pelvic fracture surgery, avulsion fragment surgery, shoulder surgery,hernia repair surgery, and surgery of an intrasubstance ligament tear,annulus fibrosis, fascia lata, flexor tendons, etc.

It is contemplated that the devices and methods of the present inventionbe applied using minimally invasive incisions and techniques to fastenmuscles, tendons, ligaments, bones, nerves, and blood vessels. A smallincision(s) may be made adjacent the damaged tissue area to be repaired,and a tube, delivery catheter, sheath, cannula, or expandable cannulamay be used to perform the methods of the present invention. U.S. Pat.No. 5,320,611 entitled “Expandable Cannula Having Longitudinal Wire andMethod of Use” discloses cannulas for surgical and medical useexpandable along their entire lengths. The cannulas are inserted throughtissue when in an unexpanded condition and with a small diameter. Thecannulas are then expanded radially outwardly to give a full-sizeinstrument passage. Expansion of the cannulas occurs against theviscoelastic resistance of the surrounding tissue. The expandablecannulas do not require a full depth incision, or at most require only aneedle-size entrance opening.

U.S. Pat. Nos. 5,674,240; 5,961,499; and 6,338,730 also disclosecannulas for surgical and medical use expandable along their lengths.The cannula can be provided with a pointed end portion and can includewires having cores which are enclosed by jackets. The jackets areintegrally formed as one piece with a sheath of the cannula. The cannulamay be expanded by inserting members or by fluid pressure. An expandablechamber may be provided at the distal end of the cannula. The abovementioned patents are hereby incorporated by reference.

In addition to using a cannula with the present invention, an introducermay be utilized to position implants at a specific location within thebody. U.S. Pat. No. 5,948,002 entitled “Apparatus and Method for Use inPositioning a Suture Anchor” discloses devices for controlling theplacement depth of a fastener. Also, U.S. patent application Ser. No.10/102,413 discloses methods of securing body tissue with a roboticmechanism. The above-mentioned patent and application are herebyincorporated by reference. Another introducer or cannula which may beused with the present invention is the VersaStep® System by Tyco®Healthcare.

The present invention may also be utilized with minimally invasivesurgery techniques disclosed in U.S. patent application Ser. No.10/191,751 and U.S. Pat. Nos. 6,702,821 and 6,770,078. These patentdocuments disclose, inter alia, apparatus and methods for minimallyinvasive joint replacement. The femoral, tibial, and/or patellarcomponents of a knee replacement may be fastened or locked to each otherand to adjacent tissue using fixation devices disclosed herein andincorporated by reference. Furthermore, the methods and devices of thepresent invention may be utilized for repairing, reconstructing,augmenting, and securing tissue or implants during and “on the way out”of a knee replacement procedure. For example, the anterior cruciateligament and other ligaments may be repaired or reconstructed;quadriceps mechanisms and other muscles may be repaired; a damagedrotator cuff may be mended. The patent documents mentioned above arehereby incorporated by reference.

Furthermore, it is contemplated that the present invention may be usedwith bariatric surgery, colorectal surgery, plastic surgery,gastroesophageal reflex disease (GERD) surgery, or for repairinghernias. A band, mesh, or cage of synthetic material or body tissue maybe placed around an intestine or other tubular body member. The band mayseal the intestine. This method may be performed over a balloon orbladder so that anastomosis is maintained. The inner diameter of thetubular body part is maintained by the balloon. The outer diameter ofthe body part is then closed or wrapped with a band; mesh, or patch. Theinner diameter of the tubular body member may be narrowed or restrictedby the band. The band may be secured to the tubular body part orsurrounding tissue with the devices and methods described herein andincorporated by reference.

It is further contemplated that the present invention may be used inconjunction with the devices and methods disclosed in U.S. Pat. No.5,329,846 entitled “Tissue Press and System” and U.S. Pat. No. 5,269,785entitled “Apparatus and Method for Tissue Removal.” For example, animplant secured within the body using the present invention may includetissue harvested, configured, and implanted as described in the patents.The above-mentioned patents are hereby incorporated by reference.

Additionally, it is contemplated that the devices and methods of thepresent invention may be used with heat bondable materials as disclosedin U.S. Pat. No. 5,593,425 entitled “Surgical Devices Assembled UsingHeat Bondable. Materials.” For example, the implants of the presentinvention may include heat bondable material. The material may bedeformed to secure tissue or hold a suture or cable. The fasteners madeof heat bondable material may be mechanically crimped, plasticallycrimped, or may be welded to a suture or cable with RF (Bovie devices),laser, ultrasound, electromagnet, ultraviolet, infrared,electro-shockwave, or other known energy. The welding may be performedin an aqueous, dry, or moist environment. The welding device may bedisposable, sterilizable, single-use, and/or battery-operated. Theabove-mentioned patent is hereby incorporated by reference.

Furthermore, the methods of the present invention may be performed underindirect visualization, such as endoscopic guidance, computer assistednavigation, magnetic resonance imaging, CT scan, ultrasound,fluoroscopy, X-ray, or other suitable visualization technique. Theimplants, fasteners, fastener assemblies, and sutures of the presentinvention may include a radiopaque material for enhancing indirectvisualization. The use of these visualization means along with minimallyinvasive surgery techniques permits physicians to accurately and rapidlyrepair, reconstruct, augment, and secure tissue or an implant within thebody. U.S. Pat. Nos. 5,329,924; 5,349,956; and 5,542,423 discloseapparatus and methods for use in medical imaging. Also, the presentinvention may be performed using robotics, such as haptic arms orsimilar apparatus. The above-mentioned patents are hereby incorporatedby reference.

Moreover, the devices and methods of the present invention may be usedfor the repair and reconstruction of a tubular pathway like a bloodvessel, intestine, urinary tract, esophagus, or other similar bodyparts. For example, a blood vessel may be intentionally severed during asurgical operation, or the blood vessel may be damaged or tom as aresult of an injury. Flexible fixation of the vessel would permit thevessel to function properly and also compress and stabilize the vesselfor enhanced healing. To facilitate the repair or reconstruction of abody lumen, a balloon may be inserted into the lumen and expanded so thedamaged, severed, or torn portion of the vessel is positioned againstthe outer surface of the inflated balloon. In this configuration, theimplants and methods described and incorporated herein may be used toapproximate the damaged portion of the vessel.

All references cited herein are expressly incorporated by reference intheir entirety.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention.

What is claimed is:
 1. An implant configured to be implanted in asubject, the implant comprising: a first body comprising a thermoplasticmaterial and having a first surface and a second surface, wherein thefirst surface is opposite the first body from the second surface; asecond body comprising at least one of a porous metallic material and aporous ceramic material; and a third body comprising at least one of aporous metallic material and a porous ceramic material, wherein a firstinterface layer between the first surface of the first body and thesecond body includes the thermoplastic material of the first bodyflowing into and solidifying within porous recesses of the second bodyto bond the first body to the second body, wherein a second interfacelayer between the second surface of the first body and the third bodyincludes the thermoplastic material of the first body flowing into andsolidifying within porous recesses of the third body to bond the firstbody to the third body, wherein the porous external surfaces of thesecond body and the third body are configured for the ingrowth oftissue, and wherein the implant has at least one cavity.
 2. The implantof claim 1, wherein an external surface of the second body and anexternal surface of the third body are coated with a therapeutic substance.
 3. The implant of claim 2, wherein the therapeutic substance isat least one of hydroxyapatite (HA) and bone morphogenetic proteins(BMP).
 4. The implant of claim 1, wherein the thermoplastic material ofthe first body comprises PEEK (polyether ether ketone).
 5. The implantof claim 1, wherein at least one of the second body and the third bodycomprises of at least one of foam metal, foam titanium, and tantalum. 6.The implant of claim 1, wherein at least one of the first interfacelayer and the second interface layer are formed by the application of atleast one of thermal energy, radiofrequency energy, and ultrasonicenergy.
 7. The implant of claim 1, wherein the implant is a spinalimplant.
 8. The implant of claim 1, wherein the cavity is configured tobe filled with graft material.
 9. An implant comprising: a first bodyformed from polyether ether ketone (PEEK) and having a first surface anda second surface, wherein the first surface is opposite the first bodyfrom the second surface; a second body formed from a porous metallicmaterial; and a third body formed from a porous metallic material,wherein a first interface layer between the first surface of the firstbody and the second body includes the PEEK of the first body flowinginto and solidifying within porous recesses of the second body to bondthe first body to the second body, wherein a second interface layerbetween the second surface of the first body and the third body includesthe PEEK of the first body flowing into and solidifying within porousrecesses of the third body to bond the first body to the third body,wherein the porous external surfaces of the second body and the thirdbody are configured for the ingrowth of tissue.
 10. The implant of claim9, wherein an external surface of the second body and an externalsurface of the third body are coated with a therapeutic sub stance. 11.The implant of claim 10, wherein the therapeutic substance is at leastone of hydroxyapatite (HA) and bone morphogenetic proteins (BMP). 12.The implant of claim 9, wherein the porous metallic material of leastone of the second body and the third body comprises at least one of foammetal, foam titanium, and tantalum.
 13. The implant of claim 9, whereinat least one of the first interface layer and the second interface layerare formed by the application of at least one of thermal energy,radiofrequency energy, and ultrasonic energy.
 14. The implant of claim9, wherein the implant is configured to be positioned between twovertebrae of the spine.
 15. The implant of claim 9, wherein the implanthas at least one cavity, and the cavity is configured to be filled withgraft material.
 16. An implant comprising: a first layer formed from athermoplastic material having a first surface and a second surface,wherein the first surface is opposite the second surface; a poroussecond layer formed from at least one of a metallic material and aceramic material; and a porous third layer formed from at least one of ametallic material and a ceramic material, wherein the first surface ofthe first body and the second body are bonded together with ultrasonicenergy, and wherein the second surface of the first body and the thirdbody are bonded together with ultrasonic energy.
 17. The implant ofclaim 16, wherein each of an external surface of the second layer and anexternal surface of the third layer are coated with a therapeutic substance.
 18. The implant of claim 16, wherein at least one of the secondlayer and the third layer comprises at least one of foam metal, foamtitanium, and tantalum.
 19. The implant of claim 16, wherein the implantis a spinal implant.
 20. The implant of claim 17, wherein thetherapeutic substance is at least one of hydroxyapatite (HA) and bonemorphogenetic proteins (BMP).